ESTIMATING VALVE LOSSES WHEN DYNAMIC EFFECTS ARE IMPORTANT

摘要

A new method has been developed for calculating valve losses in reciprocating compressors. Previously available methods have either 1) made major assumptions such as neglecting valve dynamics and the compressibility of the gas in the cylinder and as a result have been accurate for only a narrow range of conditions, or 2) used a lengthy numerical integration scheme to solve for the valve lift and cylinder pressure. The new method is designed to fill the void between these two methods and provide a reasonably accurate method applicable to the complete range of operating conditions that nevertheless is fast enough for routine use in compressor application and valve selection calculation. The technical basis for the new method is described here and comparison of its accuracy with results of a numerical integration method are given. It is shown that adequate accuracy has been achieved over a wide range of operating conditions and that an understanding of this theory leads to a greatly improved feel for valve design and selection and for the errors in previously used methods.