Development of a Flow Network Simulation Program Part III — Compressible Flow Analysis

Abstract

An in-house simulation program is developed that can conveniently be utilized to predict characteristics of compressible flow in flow network systems comprising multiple flow components. The program consists of two parts, the flow analysis for computing velocity, pressure, and density, while the thermal analysis for temperature. The flow and thermal analysis in incompressible flow were handled in the parts I and II of the paper respectively. In a numerical scheme, each flow component is represented as an element with nodes through which the element is connected to adjacent elements. The equations representing physical characteristics of elements are applied to elements, while variables are defined at nodes. In this way, a set of non-linear equations is established, which in turn is to be iteratively solved by the Newton-Raphson method. An example of the engineering tasks, an air management system for a large city bus, is introduced to demonstrate the validity and applicability of the program. Throughout the study it is found that the program can efficiently be used to evaluate capability of proposed design concepts in an early design phase of the vehicle development process.