INTERCOOLER MODEL FOR UNSTEADY FLOWS IN ENGINE MANIFOLDS

A model has been developed for intercoolers which are used to reduce t he temperature of the charge air in turbocharged internal combustion e ngines. The detailed theory for the intercooler model is presented. Th e behaviour of the intercooler is characterized by the relationship be tween the number of transfer units (N-TU) and the effectiveness (epsil on) Of the intercooler, which is assumed to be that of a cross-flow he at exchanger. The structure of the code used to implement the model is presented and the model is applied to simulate the gas dynamics in a medium-speed turbocharged and intercooled diesel engine. The results s how the predicted variation of pressure, temperature and mass flowrate across the intercooler and also the variation of intercooler effectiv eness with mass flowrate.