SIMULATION OF CAVITATING FLOWS

Abstract

The CE/SE method for solving the conservation laws is a high resolution and multidimensional numerical method that may have applications in the solution of many practical engineering problems. Its development lies in solving the integral form of the conservative equations and by discretizing the domain into Solution Elements (SE) and Conservative Elements (CE). The uniqueness of the CE/SE method lie in the fact that space and time is treated as a single entity that can be represented as coordinates in the Euclidian space. This report attempts to examine the numerical accuracy of the CE/SE method by solving some common engineering equations and problems. Good results were obtained. A CE/SE solver is then constructed to solve for a pipe flow problem with cavitation. Cavitation refers to the process of nucleation in a liquid flow where the pressure falls below the vapor pressure, the presence of Cavitation in fluids may cause certain problems in many engineering applications. A homogenous two-phrase flow model defined by a barotropic relationship between fluid pressure and density has been adopted for the cavitation model in this report. The model is applied to a Water Hammer problem which attempts to simulate the oscillatory flow in a pipe after an instance where the outlet or inlet valve is suddenly closed. It was observed from the results obtained that the current model adopted can model the pressure surges associated with the oscillatory flow but cannot model the cavitation accurately. This leads to suggestions that some conditions have to be specified in order to initiate the cavitation process.