Numerical investigation of pulsating flows in abrupt expansion pipes.

(1998) Numerical investigation of pulsating flows in abrupt expansion pipes. Masters thesis, King Fahd University of Petroleum and Minerals.


Download (2MB) | Preview

Arabic Abstract


English Abstract

Numerical investigations aimed at understanding the flow and heat transfer characteristics for the pulsating turbulent flow in abrupt-expansion pipes were carried out. The computations employed control volume method to solve the Navier-Stokes equations and energy equation. Turbulence was simulated via standard k-ε model. The study covers the downstream Reynolds number ranging from 10000 to 50000, Prandtl number varied from 0.7 to 7.0, upstream to downstream diameter ratio ranged between 0.2 to 0.6, frequency of pulsation was varied from 5 to 35. Amplitude ratio of pulsation was kept constant at 0.3 The numerical procedure used in this study was validated by comparing the steady-state results cited in the literture. The presented results consist of computed streamline distributions, mean time averaged Nusselt number, time-averaged maximum Nusselt number and location of maximum Nusselt number at different Renolds number and diameter ratios under the influence of pulsation. The results show the increase in the meantime-averaged Nusselt number with the frequency of pulsation. The effect of pulsation on the mean time-averaged Nusselt number is insignificant for fluids having Prandtl number less than the unity (around 10% increase in the value of mean time-averged Nusselt number for Prandtl number of 0.7 at frequency of 35 Hz, Reynolds number of 30000 and diameter ratio of 0.5). Whereas, this effect is appreciable for the fluids having Prandtl number greater than unity (around 30% increase in the value of meantime averaged Nusselt number for Prandtl number of 7.0 at Reynolds number of 20000, frequency of 40 Hz. And diameter ratio of 0.5). At all pulsation frequencies variation in mean time-average Nusselt number, maximum Nusselt number and its location with Reynolds number and diameter ratio exhibit similar characertistics as steady flow.

Item Type: Thesis (Masters)
Subjects: Mechanical
Department: College of Engineering and Physics > Mechanical Engineering
Committee Advisor: Said, S. A. M.
Committee Members: Habib, Mohammed A. and Mokheimer, Esmail M. A. and Badr, Hassan M.
Depositing User: Mr. Admin Admin
Date Deposited: 22 Jun 2008 13:54
Last Modified: 01 Nov 2019 13:54