Simulation of water flushing in an enclosure

• Main Author: Koh, Jason Ming Jun.
• Other Authors: Ng Yin Kwee
• Format: Final Year Project
• Language: English
• Published: 2013
• Subjects: DRNTU::Engineering::Mechanical engineering::Fluid mechanics
• Online Access: http://hdl.handle.net/10356/54193
• Institution: Nanyang Technological University

This report seeks to explore the interactions of water flow with respect to air and the enclosure walls using computer simulation tools and appropriate turbulent models of CFD commercial software. The purpose of this study is thus to simulate a realistic model which can thus be used to study the influence of various factors on the efficiency of flushing. This is achieved by firstly looking into the various turbulence models available in the commercial software Ansys Fluent, namely the Standard K-Epsilon Model, RNG K-Epsilon Model and Realisable K-Epsilon Model, the Standard K-Omega Model and the SST K-Omega Models. Comparisons were made between the simulation results obtained through these models to identify the difference in their capabilities. Parametric tests were then carried out to evaluate the influence of the inlet water velocity and pressure on water behaviour in flushing, with regards to the surface contour of water as well as the efficiency of flushing. It was observed that the Realistic K-Epsilon Model and the SST K-Omega Models are relatively more accurate in performing the simulations dues to various factors that they take into consideration in the derivation of their equations. The SST K-Omega Model was then adopted to perform the parametric studies, which indicated that the inlet water velocity is indeed a factor which poses significant influence on the behaviour of water in the flushing system. However, one also has to take into account the structure of the flushing system as there exists an optimum inlet water velocity for differing structures. It was also found the inlet pressure poses little influence over the behaviours of the water in the flushing system, but further experiments involving a larger variance of pressures across differing models could be conducted to further validate this.