Numerical study on prediction of icing phenomena in intake system of diesel engine: Operating conditions with low-to-middle velocity of inlet air

Abstract

A Numerical study is performed for generated condensation and icing phenomenon of the intake system for diesel engines when blow-by gas discharged to the intake system in the crankcase is mixed with cold air under low and medium RPM conditions. After ensuring the model reliability by comparing the icing inside the vehicle with the wind tunnel test data and the CFD simulation data, the icing was predicted under various driving conditions. CFD simulation can be used to predict and compare the amount of icing that occurs in different operation points and analyze the key factors that influence icing formation. Flow analysis is performed numerically using ANSYS Fluent, where condensation and icing are predicted using FENSAP-ICE. The variable affecting the icing the most significantly is the outside air temperature, where a lower temperature increases the amount of icing. However, when comparing the eight operation points, the amount of icing was the lowest when the inflow air and the discharged blow-by gas velocity were similar representing the amount of icing decreases as the mixture of intake air and blow-by gas increases. Although the outside air temperature and relative humidity cannot be controlled, controlling the blow-by gas discharge rate can reduce internal icing.