# how to calculate polytropic efficiency of centrifugal compressor

Support WINGS OF AERO. Volumetric flow at suction conditions is … Discharge conditions can also be determined from: (13) η P is the polytropic efficiency Example #3 19 CENTRIFUGAL COMPRESSOR 6 manual VI. Polytropic Head ← Turbine isentropic efficiency – Samarth Mittal → Polytropic efficiency of Turbine Calculator – Samarth Mittal. Table 1. Leave a Reply Cancel reply. Sketch the cycle on a p-V diagram. To determine adiabatic and polytropic efficiency, use the following chart and equations. ⋅ the polytropic efficiency of the compressor is identical, i.e T 3 is determined from T3 p3 pc the polytropic efficiency that is the same as the two stages = since polytropic efficiency approaches isentropic efficiency for pressure ratio ~ T1 p1 1, this is the same as saying that for a compressor … Either the polytropic or adiabatic head can be used to calculate horsepower as long as the polytropic or adiabatic efficiency is used with the companion head. However, in short to calculate the discharge temperature T2=T1*r^((n-1)/n) where r is the pressure ratio As you have the mass flow calculate the density at suction conditions from P1/(Z1*R*T1) where R is the Gas Constant. COMPARISON OF POLYTROPIC AND ISENTROPIC EFFICIENCY OF NATURAL GAS COMPRESSOR CALCULATED USING ASPEN HYSYSAND USING MANUAL CALCULATIONS MUHAMMAD WAQAS MANZOOR PROCESS ENGINEER Contact: engr.waqasmanzoor@gmail.com 2. Jiri Oldrich ... new method is based on numerical solution of basic definition equation of polytropic change in form edH = Vdp where “polytropic efficiency” e has constant value along the whole polytropic path. It means that the calculated power of the compressor will be (1/0.76=1.32) 32% higher when calculated with the 13 th edition compared to the 12 th. Polytropic efficiency of the compressor is defined by the formula given as: It is defined for the polytropic processes. Polytropic efficiency per stage of 85% is normal for quantity constant. A chart is then used to calculate the polytropic coefficient of the gas, then the discharge temperature calculated and then the actual power needed thanks to the formula 1 above. Advanced Polytropic Calculation Method of Centrifugal Compressor Jiri Oldrich. Centrifugal compressors : η is calculated from the polytropic efficiency given by the manufacturer. is to be brought back to its initial state what should be the polytropic index? First, the required head is calculated. Also compute the power developed if the number of cycles executed per minute is 300. Compressor efficiencies Reversible adiabatic(or isentropic efficiency), η IS: (11) W s is determined from eqn (4) Centrifugal compressors’ efficiency given by polytropic efficiency, η P: (12) Polytropic efficiency > adiabatic efficiency. Centrifugal compressors are best discussed by going through a calculation procedure and discussing each part. It seems to be a very huge difference for the same compressor! A polytropic process is a thermodynamic process that obeys the relation: … within a "polytropic compression" process like gas through a centrifugal compressor. Presentation on Calculation of Polytropic and Isentropic Efficiency of natural gas compressors 1. We ask you, humbly: don’t scroll away. The total feed gas volumetric flow rate was 101 MMSCFD (2.86×10 6 Sm 3 /d). calculate the network interaction of this cycle. For a centrifugal compressor for example, the polytropic efficiency is often close to 76%. The gas mixture with the composition shown in Table1 at 105 °F (40.6 °C) and 115 Psia (793 kPa) is compressed using a single-stage centrifugal compressor with the polytropic head and efficiency curves shown in Figures 1 and 2 at a speed of 7992 rpm. Sep 26, 2013 … Selection Of A Reciprocating Or Centrifugal Compressor a. Parameters …. Reply. Adiabatic and polytropic efficiency, use the following chart and equations compute the power developed if the number cycles... 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