DIMENSIONLESS RELATIONS FOR CALCULATING AND DESIGNING RECIPROCATING EXPANSION ENGINES

摘要

Reciprocating expansion engines (REEs) are used very widely as expansion engines to produce artificial cold and as pneumatic motors to obtain mechanical energy. A feature of those designs is that they have devices for controlling gas separation. Replacing forced gas separation of an REE by self-acting valves improves their energy, weight and size, cost, and other characteristics. The range of stable operation for an REE with self-acting valves is characterized by a combination of the operating and design parameters of the valves and engine as a whole. The principal characteristics are the initial pressure p_(in), shaft speed n, size of relative dead space a, the type, stiffness C_(sp) and number n_(sp) of springs, and the maximum lift h_(max) of the closing members of the valves. Individually, those characteristics carry some information, but their use when developing new designs of engines is difficult and limited. It is thus more expedient to represent the data of experimental research in the form of generalized variables in accordance with the similarity theory.