Heat Transfer Measurements on a Simple Model Representing a Poppet Exhaust Valve in an Outflowing Stream

Abstract

There exists no published information from which the heat transfer between the exhaust gases of a reciprocating engine and the exhaust valve may be calculated with reasonable confidence. Such information is needed for the application of cycle synthesis calculations to the analysis and prediction of the thermal loading of the valve, which is a critical component in that respect. Measurements obtained on a simplified poppet valve model in steady flow are presented. The heat transfer coefficients measured are shown to be at variance with the empirical pipe-flow equations which have previously been employed in such calculations. They can be represented by Nu = aRe^0.58 where the factor a is a function of lift/diameter ratio.