Numerical and Experimental Investigation of Water Cooled Reciprocating Air Compressor Used in Automotive Applications

Most of the heavy commercial vehicles are installed with Pneumatic brake system where the medium is a pressurized pneumatic air generated with the reciprocating air compressor. Heating is an undesirable effect of the compression process during loading cycles as reciprocating air compressors are concerned. Therefore it is necessary to reduce the delivery air temperature of compressor for safer operation of downstream products. The present investigation deals with the measurement of the delivery air temperature of a typical 318 cc water cooled compressor. A through steady state conjugate heat transfer analysis is conducted for the given speed and with the specification cooling water flow rate to predict the delivery air temperature. Pressure drop across the cooling water flow path has been measured and optimum flow rate is arrived to meet the design requirement. The results of characteristic analysis and comparative research show that the cooling system can obviously reduce the cylinder wall temperature, internal parts and other parts like gaskets to improve the fatigue life of the components. The measured and simulated results like temperature rise of cooling water due to convection heat transfer and delivery air temperature shows the good correlation with the test results. FLUENT CODE was used to perform the simulation, and the standard turbulence k-ε model was adopted in addition to the energy. CFD analysis provides insights into the flow behavior inside the compressor flow path that cannot be captured in the physical testing.