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Module-1 Syllabus, 1.Introduction to Mechanical Engineering (Overview only): Role of Mechanical Engineering in Industries and SocietyEmerging Trends and Technologies in different sectors such as Energy, Manufacturing, Automotive, Aerospace, and Marine, sectors and contribute to the GDP., 2.Steam Formation and Application: Formation of steam and thermodynamic properties of steam (Simple Problems using Steam, Tables), Applications of steam in industries namely, Sugar industry, Dairy industry, Paper industry, Food processing industry for, Heating/Sterilization, Propulsion/Drive, Motive, Atomization, Cleaning, Moisturization, Humidification, 3.Energy Sources and Power Plants: Review of energy sources; Construction and working of Hydel power plant, Thermal power, plant, Nuclear power plant, Solar power plant, Tidal power plant, Wind power plant., 4.Introduction to basics of Hydraulic turbines and pumps: Principle and Operation of Hydraulic turbines, namely, Pelton, Wheel, Francis Turbine and Kaplan Turbine. Introduction to working of Centrifugal Pump., Laboratory Components:, 1.Visit any one Conventional or Renewable Energy Power Plant and prepare a comprehensive report., 2. Demonstration of Components of any one Turbomachine through Cut Sections., 3. Visit to an Industry using steam for their process and prepare a comprehensive report., , Mechanical Engineering is branch of engineering which create and develop mechanical systems for human, comfort deals with principles of force, energy, and motion., , Q. Discuss the role of Mechanical Engineering in Industries and Society:, Mechanical engineers work in factories/industry, Government offices, consultant engineer, laboratories or testing, facilities as teachers, managers, designers, or researchers. Some mechanical engineers work in sales and product, quality control or equipment maintenance. Mechanical Engineers role in society are listed below, • Eliminates excessive usage of resources by optimizing and improving efficiency., • To build things that make the world a better living place., • Reduces human effort and makes work easy., • Without machine we can’t manufacture any electrical or electronic device and can’t transfer electricity., • Without molding we can’t produce a single brick for civil construction, • Without design we can’t make mother boards and there no scope for software., , Without mechanical engineering, we would not have things like engines, generators, elevators, Refrigerators or, even air conditioning, design and analyze manufacturing plants, industrial equipment and machinery, road, sea,, and air transport systems., Dept. of Mechanical Engg, Bheemanna Khandre Institute of Technology, Bhalki,, , Dr.Rajashekar Matpathi, M.E,Design ,Ph.D, , 1
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Q. What do you mean by GDP? Discuss its categories, Gross domestic product (GDP) is National Income i.e., the total market value of all the finished goods and, services produced within a country's borders in a specific time period. GDP = G + C + I + (X - M), GDP = Government Expenditure +Consumer Spending+ Investment + (Exports - Imports), Though GDP is typically calculated on an annual basis, it is sometimes calculated on a quarterly basis as well., It can be calculated into two categories:, Nominal GDP: It refers to the GDP at the current market prices i.e., the GDP is calculated as per the market, prices for the year for which the GDP is calculated., Real GDP: It refers to the GDP at base year prices i.e., the GDP is calculated as per the market prices in the, base year. Thus, the Real GDP negates the inflation in goods and services., In case of high rate of inflation, the nominal GDP would be higher than the real GDP. However, in case of, deflation, the real GDP would be higher than the nominal GDP., Estimates of National Income for 2020-21, Real GDP: Real GDP at Constant (2011-12) Prices in the year 2020-21 is now estimated to be at Rs 135 lakh, crores in comparison to Rs 145 lakh crores in 2019-20. The GDP growth rate is -7.3% in the year 2020-21 in, comparison to 4% growth rate registered in the year 2019-20., Nominal GDP: GDP at Current Prices in the year 2020-21 is now estimated to be at Rs 197 lakh crores in, comparison to Rs 203 lakh crores in 2019-20. The GDP growth rate is -3% in the year 2020-21 in, comparison to 7.8% growth rate registered in the year 2019-20., Q. Discuss Emerging Trends and Technologies in Energy sectors and contribute to the GDP:, As economies grow, energy demand increases; if energy is constrained, GDP growth pulls back in turn. Once, the pandemic is under control, demand and emissions may easily return to pre-pandemic levels. Hence, keeping, work efficiency at a high level will be a primary focus. And to accomplish this goal energy sector must shift, its working strategy into a new direction and that is “emerging trends in renewable energy”., 1) Renewable, Renewable is one of the emerging trends in energy sector. This Renewable energy trend helps to safeguard the, environment by emitting little to no harmful pollutants. The fundamental premise of renewable energy is to, obtain it from a consistent source in the environment, such as the sun, wind, or geothermal sources. The source, is then converted into useful power or fuel., A variety of technologies that address various facets of generating power and heat from renewable sources is, one of the latest technology trends in renewable energy. This involves lowering the cost of building renewable, infrastructure and enhancing the efficiency of power generation., 2) Internet of Energy (IoE), In the traditional method, during the time of construction, the electric power system uses the central, architecture, and this poses a number of obstacles to the industry. And here IoE comes into the frame. It helps, to recognize some of the challenges and accordingly propose the best efficiency and optimal design to build an, energy system., Technology trends in the energy industry refer to automate the power infrastructure in order to manufacture, and produce energy., Benefits:, • Reduce insufficiency, • Make the transmission of energy more productive, • Reduce the expenses, • Decrease in the wastage of energy, 3) Energy Storage, Energy storage is one of the effective energy industry emerging trends. Energy storage permits steady pricing, by proactively maintaining demand from consumers., Dept. of Mechanical Engg, Bheemanna Khandre Institute of Technology, Bhalki,, , Dr.Rajashekar Matpathi, M.E,Design ,Ph.D, , 2
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In response to shifting energy demands and technological advancements, the energy storage business has, evolved, adapted, and innovated during the last century. Energy storage systems offer a diverse set of, technological solutions for improving our power supply to build more resilient energy infrastructure and save, money for utilities and customers., The many methods of energy storage can be classified into five categories based on their technology:, • Batteries, • Thermal, • Mechanical, • Pumped hydro, • Hydrogen, It has the potential to save consumers money while also improving dependability and resilience, integrating, power sources, and reducing environmental impacts., 4) Blockchain, Blockchains or distributed ledgers are emerging technology trends in the energy industry that has drawn, significant interest from energy supply firms, startups, financial institutions, governments, technology, developers, and the academic community., Blockchain technology proposes to combine all energy stakeholders under a single decentralized system., Electricity producers, metering operators, distribution network operators, and traders potentially avail from, utilizing smart contracts. These agreements ensure that all energy-related transactions are routed through a safe, and immutable network, reducing the risk of losses. Blockchain also can achieve some degree of equity, between energy generators and consumers. Therefore, we could say that Blockchain has the potential to, transform the energy sector., It has been estimated that after the pandemic the demand and consumption of power will dramatically, increase. Thus, during that pressurize period along with meeting consumer demand business has to consider, the factors that will improve the efficiency., Q. Discuss Emerging Trends & Technologies in Manufacturing & contribute to the GDP:, India has become one of the fastest growing economies in the world over the last two decades, undoubtedly, aided in this performance by economic reforms. The striking aspect of India’s recent growth has been the, dynamism of the service sector, while, in contrast, manufacturing has been less robust. The Manufacturing, sector’s contribution to the GDP has stagnated at 16%, raising questions about India’s development model,, including its sustainability, especially for generating adequate employment. Currently, India’s manufacturing, sector contributes about 16% to the GDP, and India’s share in world manufacturing is only 1.8%. This is in, stark contrast to China; where manufacturing contributes 34% to the GDP and is 13.7% of world manufacturing, – up from 2.9% in 1991. India’s growth has been on the back of a booming services sector which contributes, 62.5% of the GDP. These statistics clearly indicate that while manufacturing has not been the engine of growth, for the Indian economy, it now needs to grow at a much faster rate. With changing global realities, the, manufacturing sector will need to be the bulwark of employment creation over the next decade, in contrast to, current employment of only 9% of India’s working population. India’s long touted demographic dividend can, only then be sufficiently exploited through the systematic growth of this sector., In order to create a paradigm shift in the manufacturing sector, it is essential to consider the objectives over a, longer timeframe, such as 15 years. The National Manufacturing Policy, which was introduced in 2011, states, these objectives and these are the underlying objectives that the Plan aims to achieve as well. These objectives, are:, 1. Increase manufacturing sector growth to 12-14% over the medium term to make it the engine of growth for, the economy. The 2 to 4 % differential over the medium-term growth rate of the overall economy will enable, manufacturing to contribute at least 25% of the National GDP by 2025., 2. Increase the rate of job creation in manufacturing to create 100 million additional jobs by 2025. Emphasis, should be given to creation of appropriate skill sets among the rural migrant and urban poor to make growth, inclusive., Dept. of Mechanical Engg, Bheemanna Khandre Institute of Technology, Bhalki,, , Dr.Rajashekar Matpathi, M.E,Design ,Ph.D, , 3
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3. Increase ‘depth’ in manufacturing, with focus on the level of domestic value addition, to address the national, strategic requirements., 4. Enhance global competitiveness of Indian manufacturing through appropriate policy support., 5. Ensure sustainability of growth, particularly with regard to the environment., Q. Discuss Emerging Trends & Technologies in Automotive &contribute to the GDP:, Along with various sector, automotive also witnessed a slow down during pandemic due to decrease in sales., However, the industry has started to rebound and gives an array of hope to everyone. So here are few tech trends, that will transform the automotive manufacturing industry in 2021., The automobile industry is supported by various factors such as availability of skilled labour at low cost, robust, R&D centres, and low-cost steel production. The industry also provides great opportunities for investment and, direct and indirect employment to skilled and unskilled labour., Indian automotive industry (including component manufacturing) is expected to reach US$ 251.4-282.8 billion, by 2026., The Indian auto industry is expected to record strong growth in 2021-22, post recovering from effects of, COVID-19 pandemic. Electric vehicles, especially 2 wheelers, are likely to witness positive sales in 2021-22., , In India, certain EVs can already outperform their fossil-fuel-based counterparts. The year 2021 could bring, more delight to the lives of Indian EV enthusiasts. The space has heated up considerably ever since international, players have announced their foray into the Indian market. It might prompt EV automakers to hasten their, product timelines while amplifying the R&D initiatives. We might see sizable advances in battery capacity,, charging time, conducive infrastructure and vehicle range owing to the development., , Dept. of Mechanical Engg, Bheemanna Khandre Institute of Technology, Bhalki,, , Dr.Rajashekar Matpathi, M.E,Design ,Ph.D, , 4
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What needs to be noted here is also the fact that one of the biggest limitations of an EV is its battery. The EV, battery constitutes nearly one-fifth of the weight of the car. At the same time, it occupies a lot of space and leads, to design-related limitations, wherein there are challenges such as less legroom. Here, Hydrogen-powered, vehicles can make a world of difference. For the uninitiated, Hydrogen-powered vehicles are basically Electric, Vehicles minus the gargantuan battery. They use Hydrogen as a fuel which combines with Oxygen to produce, electricity for the motor and water as a byproduct., In 2020, the MoRTH issued a notification to amend Central Motor Vehicles Rules, 1989, and include safety, evaluation of vehicles driven by hydrogen fuel cell technology. Nearly a year down the line, India is anticipating, its first hydrogen-powered vehicle with import approval in place. The vehicle comes equipped with three, hydrogen fuel tanks that extend the range of a whopping 1,000 KMs to its customers., Hydrogen-powered vehicles might start a new chapter in India’s clean mobility drive and the automotive, industry, at large., Robotic Process Automation (RPA): Robotic Process Automation is nothing new for the automobile segment., It is heavily used in certain manufacturing processes including spray painting, brazing, and so forth. But the use, of RPA in India is still limited as the majority of processes are led manually. The COVID-19 outbreak will, prompt more automakers to change the status quo and automate processes as much as possible. It will enable, them to ensure optimal operations even in dynamic situations, such as now. The development will further lead, to the upskilling of the automotive workforce with the introduction of specialized job roles., Q. Discuss Emerging Trends & Technologies in Aerospace & contribute to the GDP:, Despite a mixed economic forecast for the aerospace and aviation industry, engineers who embrace new, technologies, lifelong learning and flexibility should fare well in a market that continues to be rocked by the, pandemic., Expect some turbulence in the commercial aerospace market until about 2024 as airlines slowly build up the, passenger traffic and capacity decimated by COVID, according to a recent Deloitte report. Orders for new, aircraft and rotorcraft will be far below pre-pandemic levels for at least the next 18 months, affecting the entire, commercial aerospace supply chain, from large OEMs to small after-market parts companies., Engineers, however, can count on a relatively smooth ride in the space and defense industries. Space launches, and related services remain in line with previous years. Increased funding and declining costs have helped fuel, opportunities in satellite broadband internet, while Space Force, a new branch of the military, is expected to, draw the public-sector investment needed to support fresh engineering jobs, R&D and new technologies. The, Air Force also continues to adopt digital manufacturing techniques and recently launched several programs, of air and space game in 2021 to nurture and hire engineers interested in structural materials, additive, manufacturing, sensors, AI, data analytics, Augmented reality, and autonomy. AI algorithms are helping, route aircraft in more efficient ways, virtual enemies are training pilots mid-flight, and autonomous, wingmen are scouting the skies ahead., Here’s some of the major engineering technologies and trends the aerospace and aviation industry, including, defense and the aftermarket, will leverage as it recovers from the ravages of COVID-19., 1.Electric Propulsion: In efforts to achieve sustainable air travel, global companies and agencies, both big and, small, are developing new forms of electric propulsion systems. Rolls-Royce’s ACCEL (Accelerating the, Electrification of Flight) division in September successfully launched its Spirit of Aviation electric plane. A, 400-kW, 500+hp electric powertrain, using what Rolls Royce calls the most power-dense battery pack ever, assembled for an aircraft, powered the plane for a 15-minute flight over England. Back in the states, NASA, continues to develop new technologies and craft through the many programs associated with its, Electrified Aircraft Propulsion research. The agency partners with a handful of smaller companies, such as, JOBY and Elctra.aero, that have gained attention for their innovations., Many of these new aircraft are being developed for the emerging regional and urban air mobility markets. The, aircraft are designed to decrease carbon emissions, engine noise, and takeoff space. The entire space is an, Dept. of Mechanical Engg, Bheemanna Khandre Institute of Technology, Bhalki,, , Dr.Rajashekar Matpathi, M.E,Design ,Ph.D, , 5
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engineer’s dream, requiring a steady stream of new applications in computational engineering, combustion, heat transfer, fluid mechanics, aerodynamics, design and manufacturing, robotics, materials, structural, mechanics, control theory, and sensor technologies., 2.New Materials: As the industry strives for lighter, stronger components in aircraft bodies, fuselages, and, engines, it has steadily replaced aluminum with new composites and alloys, including titanium, graphite,, fiberglass, reinforced epoxy, and ceramics. Aircraft that once contained up to 70% aluminum components, can now have as little as 20%. Besides being stronger and stiffer than aluminum, the materials are corrosion and, chemical resistant, and maintain their qualities in extreme conditions. Airbus is also touting the promise of, new cost-effective, lightweight, recyclable bio-composites. Derived from biomass, biowaste, plants, crops,, and micro-organisms, they can be used alone or with standard materials, such as carbon or glass fiber., 3. 3D Printing: The global aerospace 3d printing/additive manufacturing market generated roughly $1 billion, in 2018. The number is expected to surpass $6 billion by 2026. The industry has used the technology during the, last 10 years, mainly to create nonessential plastic parts. But over the last few years, incremental advancements,, particularly in 3D metal printing, have driven new use cases for a flurry of replacement parts throughout the, cabin and more essential commercial and military components, like engine parts, wingtip fences, bearing, housing, combustion chamber protective jackets, and more. While the pandemic put a slight damper on the, aerospace 3D-printing market in 2020, it will gain more momentum, driven by new demands for lightweight, components and replacement parts., 4. Maintenance and Repair: Air-Cobot is a collaborative robot that automates visual inspection procedures., Photo: Airbus The growing use of composites will open a big window of opportunity for engineers and, technicians in maintenance and repairs. Most damage to aluminum, whether dents or bends in the body of the, aircraft or fuselage, can be seen during visual checks. Not so with components made from composites, which, require ultrasonic scanning. That’s driving investments in equipment, digitization, and skilled employees., Airbus estimates the maintenance, repair and operations sector will hit $120 billion by 2036. Airbus believes, the industry will need about 500,000 technicians to fill the demand, while Boeing puts that number at 648,000, by 2037. Almost every sector of the aerospace industry, including avionics, composites and troubleshooting,, manufacturing and design, will continue to heavily relay on digitization skills., 5. Digitization: “Digitization” is one of the most ubiquitous buzzwords in the aerospace industry for a reason., With new capabilities that quickly capture incredible amounts of data and thoroughly analyze it, digitization, technologies enable the industry to predict and identify what needs to be repaired or replaced, often before a, part actually breaks or fails, and then pinpoint the best time and employees to do the work. That influx of data, and analytics powers emerging technologies such as virtual reality, enables engineers and technicians to see all, angels of an assembly from the inside and out, and quickly access manuals and other information on handheld, devices. The new technologies will help to improve the entire supply chain and workflow, saving time and, money., Q. Discuss Emerging Trends & Technologies in Marine sectors & contribute to the GDP:, Regulatory changes and compliance are having a profound impact on the maritime industry, this is for certain., But what technologies are the leaders investing in for a sustainable and viable future of maritime?, According to the Global Marine Technology Report 2030, two technology landscapes will shape the future of, commercial shipping with a significant impact on ship design and ship operation: the first technology arena, originates from within the industry, as intense competition encourages technology sophistication and, operational efficiency in order to gain commercial advantages. The second technology area comes from other, sectors, as maturing technology is ripe for transfer to ship system design and operation to enhance safety, as, well as financial and commercial performance., Shipbuilding: Design freedom, efficient customization, waste reduction and managing virtual inventory will, drive the development for future shipbuilding technologies., Apart from the breakthrough in products’ operational efficiency, environmental impact is a major driver in, adopting new shipbuilding technologies. For instance, 90% of raw materials may be in traditional subtractive, manufacturing methods. By contrast, the introduction of additive manufacturing deposits materials only where, Dept. of Mechanical Engg, Bheemanna Khandre Institute of Technology, Bhalki,, , Dr.Rajashekar Matpathi, M.E,Design ,Ph.D, , 6
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they are required., Propulsion and Powering: Ship propulsion and power generation will be a significant area of technological, development. It is not only the scope of applicable technology, which includes future engines, alternative fuels,, propulsion energy-saving devices, renewable sources of energy, hybrid power generation, and emissions, abatement technology. It is also, and perhaps more importantly, the scale of future environmental challenges, for commercial shipping which makes propulsion and powering a key technological theme. Notably vessels, are claiming 20% reducing in fuel costs with hybrid propulsion whilst significantly reducing emissions., Smart Shipping : 10% of the new buildings will be smart ships - arguably, smart ships are not a revolution, but an evolution. Today’s concept of unmanned machinery spaces may be considered another manifestation, of the smart ship, as are data-driven services such as vessel performance monitoring and weather routeing –, the modern smart ship will integrate a variety of connected technologies to improve operational efficiency,, ship management, regulatory compliance, decision making, environmental responsibilities and also improve, safety and maintenance of vessel and crew through communication networks., Big Data and Analytics: IT infrastructure will be upgraded to retrieve, store, and process data in real, time.Archived data can be stored either onboard a ship or onshore, thanks to the support of communication, technologies. Furthermore, cognitive systems will act as data interpreters for humankind. These systems will, combine machine learning and natural language processing to offer an intuitive interface between a person, and a machine., Advanced Materials: Developing advanced materials for ship applications will be a critical component of, improving future ship performance. New features will be introduced, and multi-functional materials can be, created.A new generation of machinery will emerge with enhanced performance. Inherent smart features can, be designed for corresponding applications; these may include self-cleaning and self-repairing materials,, which would have a myriad of benefits when it comes to safety and maintenance., Robotics: There are three new types of robots that will be in use by 2030. The first will be a learning robot,, the second will be a practical robot (one that can handle an asset), and the third type will be a mini-robot,, useful for inspections in harsh, dangerous environments. These robotics will leverage: cognition, versatility,, imitation, sense and adaptability.The development of these types of robots is very closely linked to the, development of other technologies, like sensors and remote controls. These solutions require system response, times (including network delays) of less than a few milliseconds., Sensors: The utilization of sensors will represent a powerful opportunity for improvements in the efficiency, and safety of vessels and associated equipment’s. Sensors and the data they generate will have enormous, potential within the commercial shipping sector. Real-time monitoring and analysis strategies will be the key, to improving the commercial shipping sector. The capture of vessels’ top-quality data by means of robust and, reliable sensors will open up new ways of optimising vessels’ life cycles. One outcome will be to make, possible the ability to extend the life cycle of a vessel following top-standard operational criteria. This, technology will provide data which will need to be properly transferred, stored and analyzed., Communications: Today, ships generate, collect and transmit an ever-increasing volume of data. To achieve, efficient data transfer, wireless communications have been widely adopted for many years. Marine very high, frequency (VHF) installations, satellites and WiFi are just a few examples. Using a higher frequency band will, be capable of transferring multiple signals at a higher data transmission speed. With the integration of 5G,, WiFi and new generation satellites, as well as conventional marine radiocommunication networks, we will see, transformation everywhere. Stakeholders will be able to monitor live audio and high definition (HD) or 3D, video collected onboard. Radio-frequency identification (RFID) tags will support through-life asset, management, including the tracking status of cargoes, as well as structural and machinery components., Dept. of Mechanical Engg, Bheemanna Khandre Institute of Technology, Bhalki,, , Dr.Rajashekar Matpathi, M.E,Design ,Ph.D, , 7
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Q. Define Steam? Classify and Enlist its various applications? Steam is the gaseous phase of water. It, utilizes heat during the process and carries large quantities of heat later. Hence, it could be used as a working, substance for heat engines. Steam is generated in boilers at constant pressure. Generally, steam may be obtained, starting from ice or straight away from the water by adding heat to it. Steam exists in following states or types, or conditions., (i) Wet steam: When steam contains water particles(moisture) then it is known as Wet steam, (ii) Dry steam: When wet steam is further heated then all water particles get converted into Vapour and, resulted steam is called dry steam., (iii) Superheated steam: When dry saturated steam is heated to higher temperatures then steam obtained is in, superheated state. This steam is mostly used in Power generation., Applications of Steam: Water could be used as coolant and Steam is used as a working fluid for the, operation of Steam Engines (train) and Steam Turbines. Since Steam contains more energy as it has both, sensible heat and latent heat of vaporization. Steam has been a popular mode of conveying energy since the, industrial revolution. Steam is used for generating power and used in process industries such as sugar, paper,, fertilizer, refineries, petrochemicals, chemical, food, synthetic fiber, and textiles., Characteristics of steam:, 1. Highest specific heat and latent heat, 2. Highest heat transfer coefficient, 3. Easy to control and distribute, 4. Cheap and inert, The important properties of steam are:, 1. Pressure, 4. Enthalpy, 2. Temperature, 5. Internal energy, 3. Specific volume 6. Entropy, Q. Explain the formation of Steam using Temperature-Enthalpy Diagram (T-H diagram), Steam is a pure substance. Like any other pure substance it can be converted into any of the three states, i.e.,, solid, liquid and gas. A system composed of liquid and vapour phases of water is also a pure substance. Even, if some liquid is vaporised or some vapour get condensed during a process, the system will be chemically, homogeneous and unchanged in chemical composition., , Consider 1 kg of ice in a piston -cylinder arrangement as shown. it is under an Absolute Pressure say P bar, and at temperature –10C . Keeping the pressure constant, the gradual heating of the ice leads to note the, following changes in steam formation, are represented on a T-H diagram are as explained below., , Dept. of Mechanical Engg, Bheemanna Khandre Institute of Technology, Bhalki,, , Dr.Rajashekar Matpathi, M.E,Design ,Ph.D, , 8
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Region A-B: The heat given to ice increases its temperature from -10°C to 0°C. The volume of ice also, increases with the increase in temperature. At B the ice starts to melt which shows the saturated solid condition., Region B-C: The ice melts into water at constant pressure and temperature. At C the melting - process ends., There is a sudden decrease in volume at 0° C as the ice starts to melt. It is a peculiar property of water due to, hydrogen bonding, Region C-D: The temperature of water increases an heating from 0°C to 100°C The volume of water first, decreases with the increase in temperature, reaches to its minimum at 4°C and again starts to increase because, of thermal expansion. Point D shows the saturated liquid condition. During the process, a slight increase in, volume of water (saturated water) may be noted. The resulting volume is known as Specific volume of, Saturated Water (Vf), Region D-E: The water starts boiling at D. The liquid starts to get converted into Vapour. The boiling ends at, point E. Point E shows the saturated Vapour condition at 100°C and 1 bar. The resulting volume is known as, Specific Volume of Dry Steam (vg), Region E-F: It shows the superheating of steam above saturated steam point. The volume of Vapour increases, rapidly, and it behaves as perfect gas. The difference between the superheated temperature and the saturation, temperature at a given pressure is called degree of superheat., Sensible Heat: It is the quantity of heat in kJ required to raise the temperature of 1 kg of water from 0°C to, the saturation temperature at which water begins to boil at the given pressure P. If is denoted as ‘hf’, Latent Heat of Vaporization: It is the quantity of heat required to convert 1 kg of water at saturation, temperature for a given pressure to one kg of dry saturated steam, at that pressure. It is denoted as ‘hfg’, Enthalpy of Superheated Steam: The total amount of heat required to generate 1 kg of superheated stream, at the stated superheated temperature from 1 kg of water which is initially at 00 C and at a given constant, pressure is called the enthalpy of superheated steam., 𝒎𝒈, Dryness Fraction of Saturated Steam (x)= 𝒎𝒈+𝒎𝒇, It is the ratio of the mass of dry steam (mg) to the mass of total wet steam (mg +mf), where mf is the mass of, water vapor., Quality of Steam: It is the representation of dryness fraction in %: Quality of Steam = (x X 100 ), Wetness Fraction: t is another measure of quality of wet steam. It is the ratio of the mass of water vapor, (mf) to the mass of total wet steam (mg +mf), Specific volume of steam: The volume of a unit mass of steam at a given pressure is called the specific, volume of steam. It is expressed in m3 / kg., , Dept. of Mechanical Engg, Bheemanna Khandre Institute of Technology, Bhalki,, , Dr.Rajashekar Matpathi, M.E,Design ,Ph.D, , 9
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Density of Steam (): It is the ratio of mass of steam per unit of volume of steam at the given pressure and, temperature. It is the reciprocal of the specific volume. = 1/v, Internal (True) Latent Heat (internal Energy of Steam) (U), kJ/kg, It is the energy required to change the phase. Hence, it is the actual heat energy stored in the steam above, O'C. It may be calculated by subtracting the external work of evaporation from the enthalpy. U=h-W, External Work of Evaporation (W), kJ/kg, It is the fraction of the latent heat of vaporization which does an external work in moving the piston at, constant pressure due to increase in volume. W=PV, Enthalpy (h), kJ/kg: It is the total amount of heat received by 1 kg of water from O"C at constant pressure, to convert it to desired form of steam. It is the sum of the internal energy and work done at constant pressure, process, Enthalpy = Internal energy + Work done i.e. h = U + PV, Enthalpy of Wet Steam: hwet = hf + x hfg, Enthalpy of Dry Steam: hdry = hf + hfg (since for dry steam x=1), Enthalpy of Superheated Steam: hsup = hf + hfg + Cp (tsup – tsat), Advantages of Superheated Steam, (h) At a given pressure, its capacity to do the work will be comparatively higher., (i) It improves the thermal efficiency of boilers and prime movers, (j) It is economical and prevents condensation in case of Steam turbines, Disadvantages of Superheated Steam, (i) Rise in Superheated temperature poses problems in lubrication, (ii) Initial cost is more and depreciation is higher, Steam Table: All the previously mentioned properties of steam i.e. specific enthalpy, specific volume and, specific entropy each of saturated water and steam (wet, dry & superheated) vary with the change in saturation, pressure. And for a particular saturation pressure there is a fix value of saturation temperature. These properties, are required in thermo dynamic calculations where steam is used as working medium. It is quite cumbersome, to calculate each time, the value and relation between various properties. So, these are experimentally, determined and presented in the form of tables showing value of each property w.r.t either saturation, temperature or saturation pressure. These tables are called steam tables. The value of properties of saturated, steam and superheated steam are given separately. If any given pressure falls in between two values given in, table then value of concerned property on this pressure may be calculated by interpolation. The column in the, steam table showing properties of saturated stream are as given below:, , Dept. of Mechanical Engg, Bheemanna Khandre Institute of Technology, Bhalki,, , Dr.Rajashekar Matpathi, M.E,Design ,Ph.D, , 10
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P.1. Calculate the total heat of 5 kg of steam at an absolute pressure of 8 bar having dryness fraction of, 0.8. Also calculate heat in kJ required to convert the steam into dry and saturated steam., Data: m=5kg, P=8bar, x=0.8 ,, From steam tables @ pressure 8 bar, hf = 720.9 kJ/kg, hfg = 2046.5 kJ/kg,, hg = 2767.4 kJ/Kg, Sp. enthalpy of wet steam hw = hf + x.hfg == 720.9 + 0.8 x 20= 2358.1 kJ/kg, Total heat of 5 kg steam = weight of steam x Sp. Enthalpy = 5x2358.1 = 11790.5 kJ, Now total heat of 5kg dry saturated steam = 5x hg = 5x 2767.4 = 13830 kJ, Net heat required for conversion of wet steam into dry saturated steam = 13830-11790.5 = 2039.5 kJ, P.2 4 Kg of 0.5 dry steam at 6.0 bar pressure is heated, so that it becomes, (a) 0.95 dry at 6.0 bar pressure or, (b) Dry & saturated at 6.0 bar or, (c) Superheated to 300oC at 6.0 bar or, (d) Superheated to 250oC at 8.0 bar, Using steam tables determine in each case the quantity of heat required to be supplied. Take C sup for, superheated steam as 2.3 kJ/ kg K., Data: Initial Condition of steam are mass, m = 4 kg; x1= 0.5 and P = 6.0 bar, So initial enthalpy (total heat content) of 4kg steam is H1 = 4[hf +0.5hfg], From steam table, @ 6.0 bar pressure value of specific enthalpy of saturated water, hf and latent heat of steam,, hfg are given as hf = 670.4 kJ/kg; hfg = 2085.1 kJ/kg;, H1 = 4[670.4+0.5x2085.1] = 6851.8 kJ ≈ 6852 kJ, Heat Supplied, Case I Final Conditions of Steam are x2=0.95 and pressure, p=6.0 bar. So final enthalpy of steam is, H2 = 4[hf + x.hfg] = 4[670.4 + 0.95 x2085.1] = 10605 kJ, Net heat supplied = Final Enthalpy - Initial Enthalpy = 10605 - 6852 = 3753 kJ, Case II Final Conditions of Steam are pressure, p=6.0 bar. Condition is dry saturated i.e.,, x2 = 1. So final enthalpy of steam is H2 = m.hg = 4x2755.5 kJ/kg =11022 kJ, Net heat supplied = Final Enthalpy -Initial Enthalpy = 11022 - 6852 = 4170 kJ, Case III Final Conditions of Steam are pressure, p=6.0 bar, Superheated to 3000C. Form steam tables,, saturation temperature, tS at given pressure 6.0bar is ts = 158.80C. So final enthalpy of superheated steam is, H2 = m [hg + CPs (tsup -ts)] = 4[2755.5 + 2.3(300-158.8)] = 12321 kJ, So Net heat supplied = Final Enthalpy - Initial Enthalpy = 12321-6852 = 5469 kJ, Case IV Final Conditions of Steam are pressure, p=8.0 bar, Superheated to temperature, tsup = 2500C., From steam tables @ 8.0 bar pressure ts = 170.40C, hg = 2767.4 kJ/kg, So H2 = m [hg + CPs (tsup -ts)] = 4[2767.4 + 2.3(250-170.4)] = 11801.92 ≈ 11802 kJ, Heat Supplied == 11802 - 6852 = 4950 kJ, Dept. of Mechanical Engg, Bheemanna Khandre Institute of Technology, Bhalki,, , Dr.Rajashekar Matpathi, M.E,Design ,Ph.D, , 11
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P.3 Calculate the entropy and volume of 4.73 kg of superheated steam at pressure 7.8 bar and, temperature 240oC. Take Cp for superheated steam = 2.32 kJ/kg. K, Data: @ 7.8 bar, Saturation temperature ts = 169.4oC So Ts = 169.4+273 = 442.4 K, vg = 0.2461 m3/ kg; sg = 6.668 kJ/kg K, tsup = 240oC so, Tsup = 240 + 273 = 513 K, Sp.vol. of superheated Steam, = 0.2854 m3/kg, Total volume of 4.73 kg of steam = 4.73x0.2854 = 1.3498 m3, Sp. entropy of superheated steam = sg +, = 7.0115 kJ/ kg K, Total entropy of steam = 4.73x 7.0115 = 33.16 kJ/ K, P.4 A boiler is producing steam at a pressure of 15 bars and quality as 0.98 dry. It was observed that, while flowing from boiler to the place of heating through pipes, steam looses 20 kJ of heat per kg., Assuming the constant pressure, while flowing through pipe line, calculate the quality of steam at the, place of heating., Data: Pressure P=15 bar; x= 0.98; Heat loss= 21 kJ/ kg, From steam tables, @ pressure, P=15 bar, hf = 844.6 kJ/kg; and hfg = 1945.3 kJ/kg, So specific enthalpy of steam in boiler, h1 = hf + x.hfg, , = 844.6 + 0.98, , 1945.3 = 2751 kJ/kg but Heat loss = 21 kJ/kg, So net enthalpy of steam at the other end of pipe line or at the place of heating = 2751−21 = 2730 kJ/kg, To find dryness fraction of this steam x2 we know h2 = hf + x2.hfg, 2730 = 844.60 + x2 x 1945.3, , ENERGY SOURCES:, , Dept. of Mechanical Engg, Bheemanna Khandre Institute of Technology, Bhalki,, , Dr.Rajashekar Matpathi, M.E,Design ,Ph.D, , 12