Numerical simulation of the cold flow in an axisymmetric non-compressing engine-like geometry

Fluid motion within the cylinder of a piston engine has a major influence on the performance of the engine. The general motion within the cylinder and the associated turbulence affect the charge stratification, combustion and heat transfer processes. In order to predict the charge stratification, one must understand and be able to predict the turbulent mixing processes (Reynolds, 1980). There are numerous alternative turbulence modelling approaches of varying degrees of complexity, but two of them, k–ϵ turbulence models and Reynolds stress models, are commonly used in engine modelling activities. In the present study, k–ϵ turbulence model was used to predict the flow in the cylinder of a non-compressing engine-like configuration. Wall function treatment was employed in order to bridge the wall layer to the inner region. Finite volume method incorporated with hybrid (central/upwind) spatial and implicit temporal schemes, and SIMPLE algorithm (Patankar, 1980) were used to obtain numerical solutions. Results were compared with the measurements of Morse et al. (1978) and predictions of Gosman et al. (1980). Although the degree of agreement between the predictions and the measurements varies throughout the cycle and the flow field, the overall agreement is found to be satisfactory. Copyright © 1999 John Wiley & Sons, Ltd.