Date of Award

Summer 2014

Degree Type

Thesis

Degree Name

Master of Science in Mechanical Engineering (MSME)

Department

Mechanical Engineering

First Advisor

Haifeng Wang

Committee Chair

Haifeng Wang

Committee Member 1

Robert P Lucht

Committee Member 2

Gregory A Blaisdell

Abstract

A generalized empirical model for estimating the pressure drop across a channel for a given massflow rate is studied through computational fluid dynamics (CFD) simulations. It is observed that for developing laminar and turbulent flow through channels and pipes of arbitrary cross-section, the variation in the pressure drop between any two points in the flow direction with massflow rate can be well approximated by a second degree expression in massflow rate which is referred to as the empirical model in this study. In the first part of this study, a correlation between the pressure gradient and the massflow rate is derived analytically using the momentum integral approach. It is seen that the empirical model has the same format as this analytical correlation indicating that the empirical model has a good theoretical background. The second part of this study involves analyzing the coefficients of the model. A series of simple laminar and turbulent flows namely, flow through a straight channel, converging channel and a sine curve profile channel are used for examining the empirical model. This analysis reveals that though the empirical model is not precise, it is reasonably accurate for determining the characteristic curve of the system pressure loss in real-life engineering applications. It is found that the second degree term in the empirical model represents pressure loss due to acceleration of the fluid in the developing region and the first degree is due to the friction at the wall. Lastly, the performance of the model is assessed and the accuracy of the model in predicting the pressure drop is quantified.

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