Though refrigerant vapours do not strictly behave as ideal gases, the s. Feb 08, 2014 compressor is a machine used to compressed air or gas to a final pressure exceeding 241. It is the quantity of air actually delivered by a compressor in m 3 minute or m 3 sec. Pradeep, department of aerospace engineering, iit bombay. Centrifugal compressor surgebasics, mechanism mechanical. The two broad classes of compressors are reciprocating and rotary type of compressors. Average volume displaced per unit time by the piston of reciprocating compressors or by vanes, screws and lobes of rotary compressors. Reciprocating compressors contd power requirements of ideal and actual compressors optimum work for given condenser and evaporator pressures, mean effective pressure, pull down characteristics compressor discharge temperatures and need for cooling capacity control 18th lecture centrifugal compressors basic principle of dynamic. The gas turbines book in question is several hundred pages long and besides the basics, covers some of the more complex and lengthy work in recent gas turbine development. A gas compressor is a mechanical device that increases the pressure of a gas by reducing its volume. Since the discharge pressure is always more than the inlet pressure, therefore the value of compression ratio is more than unity. 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. All you need to do is just click on the download link and get it. Gas turbine engines the combustion process is replaced by a constantpressure heataddition process from an external source, and the exhaust process is replaced by a constantpressure heatrejection process to the ambient air.
The capacity of a compressor is generally given in terms of free air delivery. The change in operating gas can cause compressor surge. Figure 4 shows typical gas flow diagram in reciprocating compressor. Process gas compressors process gas compressors comprehensive api 618 compressor portfolio.
It is the volume of air delivered by compressor under the compressor intake conditions i. In centrifugal compressor, high kinetic energy of gases is converted into pressure energy in. As we seen the surge is due to the flow reversal in the compressor. Factors that affect the performance of compressors are the speed of rotation, pressure at suction, pressure at discharge, and type of refrigerant being. Compression of a gas naturally increases its temperature. The compressor from the previous example is air cooled. We understand the different customer needs in terms of specification and costefficiency. It is the actual volume delivered by a compressor when reduced to the normal temperature and pressure condition. The volume displaced or swept by piston when it moves between top dead. Multistage vapour compression refrigeration systems nptel. The piston reciprocates drawing in gas, compressing it and expelling it when the pressure inside the cylinder reaches the same level as the. The features like a rise in pressure, working pressure, mechanical design and specific speed become the basis for the classification and. A piston is driven in a reciprocating action to compress the gas.
Pdf the physics of centrifugal compressor perfromance. When the gas is air, the machine is called an air compressor. It can then be arranged multistage for greater proportions of compression. Iit kharagpur notes converted into high quality audio source nptel. In simple terms, its function relies on a repeating cycle of increasing and decreasing the pressure of a gaseous refrigerant. Gas temperature at the discharge flange of the compressor displacement. Compression process of gas in centrifugal compressor describes with fig. The work output of a turbine can be increased by expanding the gas in stages and reheating it in between, utilizing a multistage expansion with reheating. Compressors, gas turbines and jet engines mcq practice test set 01. Compressors are prime movers of gas and air in process industries. One of the advantages of the closed turbine gas cycle is that the turbine stays clean because the combustion products do not pass through it. Air is the most frequently compressed gas but natural gas, oxygen, nitrogen, and other industrially important gases are also compressed. The only difference is instead of the reciprocating motion, gas turbine uses a rotary motion throughout.
The compressors in most gas turbine applications, especially units over 5mw, use axial. Compressors, gas turbines and jet engines mcq practice test. The compression cylinders, also known as stages, of which a particular design may have from one to six or more, provide confinement for the process gas during compression. The three general types of compressors are positive displacement, centrifugal, and axial. Gas transmission pipelines, petrochemical plants, refineries and many other industries all.
Discuss multistage vapour compression refrigeration systems with flash gas removal and intercooling section 12. Centrifugal compressors still find use in smaller gas turbine engines. Gas compressor simple english wikipedia, the free encyclopedia. Nov 14, 2017 centrifugal compressor is a machine in which a particular gas or vapor is compressed by a radial acceleration by an impeller with the help of a surrounding case. Gas enter compressor through suction nozzle 1 at ps p1 measured as total pressure and become p2 as static pressure in isentropic. Modelling centrifugal compressors kate powers supervisors. Nov, 2014 the compressor work input can be decreased by carrying out the compression process in stages and cooling the gas in between fig. As gases are compressible, the compressor also reduces the volume of a gas. The gases expand doing work and finally exhausts outside. Nptel provides elearning through online web and video courses various streams.
It sucks in air from the atmosphere, compresses it. The different types of cooling compressors rotaryvane compressor a rotaryvane compressor is also known as a rotary piston compressor because the function of the vane is similar to that of a piston shown in figure 3. Pulsation dampener is made from pressure vessel and orifice. By varying these parameters, the performance of the system can be optimized. Compressor, device for increasing the pressure of a gas by mechanically decreasing its volume. What is here however, does give the reader the basic theory and pr actice of gas turbines in simple cycle and combined cycle.
Lecture series on steam and gas power systems by prof. 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. Analyse the performance of a centrifugal compressor using steady flow. A compressor is a mechanical device that increases the pressure of a gas by reducing its volume. As your partner, burckhardt compression supports you in all phases of your project. New innovations and an integral design tied process units together in the most effective and efficient ways. An air compressor is a specific type of gas compressor.
They are often some of the most critical and expensive systems at a production facility, and deserve special attention. A reciprocating compressor is a positive displacement machine in that a volume of gas is drawn into a compressor cylinders compression chamber where it is trapped, compressed and pushed out. Pdf power plant lecture notes chapter6 gas turbines. Chris budd, paul milewski, chris brace, colin copeland. A compressor is the source of high pressure gas for any liquefaction or a refrigerating system. Chapter 9 gas power cycles universiti tenaga nasional. They are used to increase static pressure of the gas and deliver it at specified pressure and flow rate in a process application. Free ppt and pdf download for compressor study mafia. For larger engines, axial compressors need lesser frontal area and are more efficient.
From the first idea until the end of your facilitys lifetime. As a result of the surge in the compressor, it may lead to damage of compressor or compressor system. A reciprocating compressor is a positivedisplacement machine that uses a piston to compress a gas and deliver it at high pressure. Rotary, positive displacement type compressors nptel. Design calculation of blade design for axial flow compressor an axial flow compressor used in gas turbine engine has constant axial velocity throughout the compressor of 152 ms, blade mean velocity of 162 ms and it is delivered 10.
Types of compressors centrifugal compressors for low p slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. 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. The pv diagram is a plot of the pressure of the gas versus the volume of the gas trapped in the compression chamber. The vane splits the space between the cylinder and the. Under the gas machinery research council 2007 program, southwest research institute has developed an application guideline to be used in the design and selection of centrifugal compressor surge. Valentini gas turbine power plants 9 mass flow rates and so this plant can be adopted on sites with low water availability. A compressor is a pump used to increase the low pressure of air to a greater pressure. Compressor is a machine used to compressed air or gas to a final pressure exceeding 241. Mar 05, 2017 lecture series on steam and gas power systems by prof.
Compression process of gas in centrifugal compressor gas compression process is presented in enthalpy versus entropy chart. It is the volume of air delivered by the compressor, and is expressed in m3min or m 3s. The central focus is on packaged complete unit air compressors, most commonly used in. It is the ratio of discharge pressure to the inlet pressure.
Modulevi reciprocating compressor applied thermodynamics 2014 vtu nptel nmeict project progress report the project on development of remaining three quadrants to nptel phasei under grant in aid nmeict, mhrd, new delhi. It is not uncommon to have pressure ratios in industrial gas turbines in the 17 to 20. Describe multievaporator systems using single compressor and a pressure reducing valve. Here we are giving you gas turbine seminar and ppt with pdf report.