Back Flow Effect on Effective Flow Area at Reed Valve Section of a Hermetic Compressor

摘要

Valve design is one of the most important aspects of compressor design. In designing the valve system for reciprocating compressors four main features related to the valve performance are sought: Fast response, high mass flow rate, low pressure drop when opened and good backflow blockage when closed. For this reason and in order to obtain an optimum valve system, it is crucial to recognize and predict the phenomena associated with the flow through the valve. The present research is to analyze the effective flow area across the valve section of a hermetic compressor with back flow condition experimentally. Mass flow rate has been an important parameter in analyzing the effective flow area at the valve section. Experimental set up being arranged in order to compute the mass flow rate through the valve section for various valve lifts. Using continuity equation for steady one-dimensional flow, mass flow rate through the valve section is calculated analytically. Effective flow area in terms of lift is obtained experimentally taking the design parameters like flow rate, discharge coefficient, area of cross section and static pressure across the valve section. The effective flow areas are higher at 60% of the valve lift in case of back flow conditions. These experimental results were compared with the analytical values with 5% variation, well with in the accepted limits. These results would be useful in optimizing the performance of reciprocating compressors.