Abstract
A number of finite difference schemes are available to study pressure fluctuation effects in unsteady pipe flows. This paper presents a comparison Of the predictions made by three such schemes of unsteadyjlow effects in a number of reciprocating compressor pipe-work systems. The finite difference schemes considered were;- a first order scheme known as the method Of characteristics, two second order schemes which were the Leapfrog method and MacCormacVs method. A reciprocating compressor simulation computer program was coupled with equations describing the cylinder thermodynamic processes with the pipe flow equations for steady non-homentropicflow. The comparison presented takes into account both the efficiency of the methods under consideration and their agreement in the prediction Of the compressor behaviour. The MacCormack's method was modified to handle processes at pipe boundaries and within gas volumes while thc Leapfrog method had to be coupled with the method of characteristics at pipe boundaries. The method of characteristics was also used independently to handle both internal meshes and pipe boundaries. The Leapfrog method was found to be more favourable in terms of computer time followed by the MacCormack's method and lastly the method of characteristics. In terms of accuracy the two second order schemes were found to be superior to the method of characteristics which is a first order accuracy scheme.
Recommended Citation
Mkumbwa, M. (1998). A COMPARISON OF THREE NUMERICAL METHODS OF SOLUTIONS OF EQUATIONS DESCRIBING UNSTEADY GAS FLOW AT PIPE BOUNDARIES IN RECIPROCATING COMPRESSOR SYSTEMS. Tanzania Journal of Engineering and Technology (TJET), 22(2), 259-271. https://doi.org/Previous Published Paper
Publisher Name
University of Dar es Salaam