Compressed air or pneumatic devices are therefore characterized by a high powertoweight or powertovolume ratio. In modern configurations of centrifugal air compressors, ultrahigh speed electric motors are used to drive the impellers. As gases are compressible, the compressor also reduces the volume of a gas. All the processes that make up the cycle are internally reversible. Because co is colorless and odorless, it is impossible for respirator wearers to detect. The central focus is on packaged complete unit air compressors, most commonly used in. At low q gas pressure has the same energy at horizontal portions of the performance curve. An air compressor is a specific type of gas compressor compressors are similar to pumps. Iit kharagpur notes converted into high quality audio source nptel. With over two million quincy qr25 air compressors currently in use, some originally installed more than 40 years ago, you can count on the quincy qrng for economical gas boosting needs. These blades impel air rearward in the same manner as a propeller because of their angle and airfoil contour. Pulsation dampener is made from pressure vessel and orifice.
In the design and testing of gas compressors, the correct determination of the thermodynamic properties of the gas, such as enthalpy, entropy and density from pressure, temperature and composition. The air is entrapped in the compartment formed by a male lobe and a female flute. Reciprocating gas compressor quincy qrng series the engineering behind the quincy qrng is best examined through the proven performance of the quincy qr25. Centrifugal compressors still find use in smaller gas turbine engines. The compressed gas association cga offers publications on handling compressed gases, such as, pamphlet p1, safe handling of compressed gases in containers. Types of compressors centrifugal compressors for low p slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. Compressors, gas turbines and jet engines mcq practice test set 01 mcq compressors edit. Lecture series on steam and gas power systems by prof. The purpose of this publication is to help users understand the basics of compressed air as a power source and to provide initial technical guidance for selecting the right air compressor for specific applications. Therefore, the highpressure air leaving the compressor can be heated by the hot exhaust gases in a counterflow heat exchanger a regenerator or a recuperator. For the love of physics walter lewin may 16, 2011 duration. Nptel video lectures, iit video lectures online, nptel youtube lectures, free video lectures, nptel online courses, youtube iit videos nptel courses. P d, discharge pressure, represents the pressure of the gas at the outlet from the compressor cylinder. Learn the working of reciprocating compressor and derivation of workdone expression.
Centrifugal compressor surgebasics, mechanism mechanical. This section includes select lecture notes for the course excluding lessons on aircraft propulsion and jet engine rotordynamics. History from compressor development point of view lowspeed steam engine driven compressors highspeed electric motor driven compressors rotary vane compressors centrifugal compressors screw compressors scroll compressors history of air conditioning module 2. A compressor is a mechanical device that increases the pressure of a gas by reducing its volume. They are often some of the most critical and expensive systems at a production facility, and deserve special attention. The combustion process is replaced by a heataddition process from an external source. If the flow of air through the compressor is perpendicular to its axis, then it is a. Air behaves like the ideal gas and follows the laws. Physical hazards of compressed gas cylinders pressure weight stability mechanical failure movement. Refrigeration and airconditioning nptel online videos.
As we seen the surge is due to the flow reversal in the compressor. At the higher discharge pressure and temperature, the gas density is also higher, so the mass of gas occupies a smaller volume i. Pradeep, department of aerospace engineering, iit bombay. Introduction to fluid machines and compressible flow by prof. Applications 3rd lecture applications of refrigeration and air.
Describe commercial refrigeration systems using centrifugal compressors. A gas compressor is a mechanical device that increases the pressure of a gas by reducing its volume. Find materials for this course in the pages linked along the. They are best suited when the demand of air or gas is constant and excessive. Lecture 2 refrigerant compressors and development youtube. It is also employ in the operation of lifts, rams, pumps etc. Portable air compressors 30 stationary air compressors 18 compare. Machinery fault diagnosis and signal processing by prof. The compressed gas safety manual was created to ensure the safe use of compressed gases and all associated equipment by depaul university employees and students, and to ensure compliance with applicable osha and industry consensus standards. Applications of air compressors how to use quincy compressor. However, there exist a large number of fluid machines in practice, that use air. If you have a home shop using pneumatic tools, a bigger sized stationary tank would provide a better air source. From the first idea until the end of your facilitys lifetime. Feb 08, 2014 compressor is a machine used to compressed air or gas to a final pressure exceeding 241.
Rotary, positive displacement type compressors nptel. Compressor, device for increasing the pressure of a gas by mechanically decreasing its volume. Read here to know about various types of air compressors used and get a clear inside view of each type of compressor with the attached pictures. Centrifugal compressor is one of the most simple and efficient way to obtain or produce compressed air. Mohanty,department of mechanical engineering,iit kharagpur. Kerrebrock and subsequently adapted by manuel martinezsanchez. Most homeuse air compressors will be small enough to be moved around on wheels or carried around. Figure 4 shows typical gas flow diagram in reciprocating compressor. High quality compressed air is by definition 100% oil free class 0.
The working fluid is air, which continuously circulates in a closed loop and always behaves as an ideal gas. Compressors, gas turbines and jet engines mcq practice test set 01 mcq compressors edit practice test. In figure 1, p s, suction pressure, represents the pressure of the gas at the inlet to the compressor cylinder. One part of the course is on ic engines and it focuses onthe thermodynamic cycles for different fuels suitable for automobiles. When air is sucked into the compressor, it brings with it water vapour. The features like a rise in pressure, working pressure, mechanical design and specific speed become the basis for the classification and differentiation. It is also the biggest source of heat generation due to the motor inefficiency and gas compression. In gas turbine engines, the temperature of the exhaust gas leaving the turbine is often considerably higher than the temperature of the air leaving the compressor. Pdf the physics of centrifugal compressor perfromance. Gas transmission pipelines, petrochemical plants, refineries and many other industries all. The air compressors and gas compressors are used in many industries like electronics, automobiles, steel, chemicals, food processing industry, machinery, pharmaceuticals, construction, civil engineering, glass, pulp and paper, and theme parks. Apr 14, 2017 gas is compressible, but liquid is not. The pv diagram is a plot of the pressure of the gas versus the volume of the gas trapped in the compression chamber.
The compressors in most gas turbine applications, especially units over 5mw, use axial. While the gas generator, composed of the compressor, combustor and turbine, is the heart of any gas turbine engine, the overall performance of the propulsion system is strongly influenced by the inlet and the nozzle. We understand the different customer needs in terms of specification and costefficiency. Download chapters of the compressed air and gas handbook for free. As a result of the surge in the compressor, it may lead to damage of compressor or compressor system. Air is the most frequently compressed gas but natural gas, oxygen, nitrogen, and other industrially important gases are also compressed. Lecture 11 12 industrial gases carbon dioxide distillation. Process gas compressors process gas compressors comprehensive api 618 compressor portfolio. After expanding the cold air goes out through the outer coil, is then recompressed to 200 atm pressure, cooled by water and then again allowed to transverse the inner coil. Read here to know about the basics of compressing air and appreciate the reason for air compressor following polytropic or isentropic compression instead of isothermal or adiabatic one. Lowspeed steam engine driven compressors highspeed electric motor driven compressors rotary vane compressors centrifugal compressors screw compressors scroll compressors history of air conditioning module 2. A reciprocating compressor is a positivedisplacement machine that uses a piston to compress a gas and deliver it at high pressure. Describe various air cycle refrigeration systems section 9.
Jul 12, 2017 the air compressors and gas compressors avails air pressure for measuring instrument. As the rotors turn, the compartment becomes progressively smaller, thereby compressing the entrapped air. Chapter 2 the general design of a pneumatic system and. Compression of a gas naturally increases its temperature. Unit 7 air compressors working of a single stage reciprocating air compressor, calculation of work input, volumetric. Concept of air pollution control engineering control 1 control at the source of emission 2 control for receptors e. These washedout lube oil may admittedly not be too great a problem for compressors for air, nitrogen or hydrogen, but positively these residual oils are difficult to be handled from e. Gas enter compressor through suction nozzle 1 at ps p1 measured as total pressure and become p2 as static pressure in isentropic. When the gas is air, the machine is called an air compressor compressors are similar to pumps.
In many cases, a properly designed heat recovery unit can recover anywhere from 50 to 90 percent of this available thermal energy and put it to useful work heating air or water. Unlike other sources of power, no conversion from another form of energy such as heat is involved at the point of application. The change in operating gas can cause compressor surge. Air compressors were designed to compress air to higher pressures and harness this potential energy source. Compressors, gas turbines and jet engines mcq practice test. Atmospheric air is the cooling medium for most of the refrigeration. Compressors, gas turbines and jet engines mcq practice.
The handbook is the authoritative reference source for general information about compressed air. Compressor is a machine used to compressed air or gas to a final pressure exceeding 241. Air compressors compressed air and gas institute cagi. The importance of humidity to air compressors is as follows. The rotor, turning at high speed, takes in air at the compressor inlet and impels it through a series of stages. They also sell videos on the subject of compressed gases. Oil and natural gas sector compressors ourenergypolicy. Compression process of gas in centrifugal compressor describes with fig.
Positive displacement compressors cab be further divided into reciprocating and rotary compressors. Som,department of mechanical engineering,iit kharagpur. M d atrey, department of mechanical engineering, iit bombay a compressor is the source of high pressure gas for any liquefaction or a refrigerating system. Due to the discontinuity of gas flow of reciprocating compressor, gas pulsation will occur if excitation frequency is near or equal to natural frequency of gas column in the system. When the air is compressed the pressure and the temperature of the air goes up and the result is that the compressed air will have a relative humidity of about 100% and it will be warm.
Compressors, fans, and blowers are devices which are designed in such a way that they deliver gas at a pressure which is more than the genuinely existing pressure. As your partner, burckhardt compression supports you in all phases of your project. This results in a compact compressor without a gearbox and associated oillubrication system, thus making it oilfree and appropriate for applications that require 100 percent oilfree air. This type of air compressor can be powered by either an electric motor or a gas engine, which allows for remote uses and ease of mobility. The gas turbine operates on the principle of the brayton cycle, where compressed air is mixed with fuel, and burned under constant pressure conditions. This is especially true for high m o flight, when a major portion of the overall temperature and pressure rise of. Food processing industry depends highly on this type of compressor as it can provide oil free compressed air which are. In a reciprocating compressor, a volume of air is drawn into a cylinder, it is trapped, and compressed by piston and then discharged into the discharge line. Reciprocating compressor, working and derivation of.
Co combines readily with hemoglobin in red blood cells and prevents the transfer of oxygen to the tissues, causing oxygen starvation or hypoxia. Applications 3rd lecture applications of refrigeration and air conditioning a comfort air conditioning. Discuss the performance aspects of ideal reciprocating compressors with clearance. An important application of thermodynamics is the analysis of power cycles through which the energy absorbed as heat can be. A positivedisplacement compressor traps air into a compression chamber and reduces the volume of the chamber. The nature of the working fluids can be classified into two groups. Chapter 9 gas power cycles universiti tenaga nasional. The gas is allowed to suddenly expand by opening the valve, which result in decrease of temperature of air.
Other part of the course hasemphasis on thermodynamic cycle of aircraft. Learn more about compressed air through the cagi smartsite, an online course of 8 modules that provide education about various aspects of compressed air systems. The cylinder valves control the flow of air through the cylinder. In other words, compressors accept a mass of gas at some initial pressure and temperature and raise that gas to a higher pressure and temperature figure 1. Compression process of gas in centrifugal compressor gas compression process is presented in enthalpy versus entropy chart. Assuming the air as a perfect gas, where m is the mass of air induced and delivered per cycle, r is the universal gas constant, where r 0. Used compressors compressors increase the pressure of a gas. Compressor performance centrifugal and axial compressors are pumping gas continuously but reciprocating is not.