Numerical analysis of heat transfer in pulsating turbulent flow in a pipe

Abstract

Convection heat transfer in pulsating turbulent flow with large velocity oscillating amplitudes in a pipe at constant wall temperature is numerically studied. A low-Reynolds-number (LRN) k-e turbulent model is used in the turbulence modeling. The model analysis indicates that Womersley number is a very important parameter in the study of pulsating flow and heat transfer. Flow and heat transfer in a wide range of process parameters are investigated to reveal the velocity and temperature characteristics of the flow. The numerical calculation results show that in a pulsating turbulent flow there is an optimum Womersley number at which heat transfer is maximally enhanced. Both larger amplitude of velocity oscillation and flow reversal in the pulsating turbulent flow also greatly promote the heat transfer enhancement.

Application of turbulent pulsating flows to the bacterial removal during a cleaning in place procedure. Part 2: Effects on cleaning efficiency

“…Thus, for flow conditions used in this study, the frequency of 2.5 Hz can be considered as optimal in the bacterial removal. On the other hand, the beneficial effect of large amplitude of pulsations is already demonstrated in many transfer processes (Keil and Baird, 1971;Paek et al, 1999;Wang and Zhang, 2005). However, it seems difficult, with this pulsations generator system, to go beyond the maximum value of amplitude fixed in this part (0.73 m/s), due to the stability problems of the installation.…”

Characteristics of heat transfer and flow of Al2O3/water nanofluid in a spiral-coil tube for turbulent pulsating flow

“…The heat transfer coefficients of such a flow are affected by several parameters such as inlet fluid temperature, boundary condition, Reynolds number, Prandtl number, type of pulsator, location of pulsator, pulsation frequency, pulsation amplitude, length to diameter ratio and secondary flow. Having higher velocity gradient at the tube wall, producing higher velocity at some moments, pressure gradient reversal during a period, producing forced circulation in the fluid and promoting the formation of eddies are the most important mechanisms of the heat transfer enhancement [10,14,[48][49][50].…”

Oscillating Flow and Heat Transfer of Single Phase in Capillary Tubes

“…Several investigators (Wang and Zhang 2005) have numerically investigated fluid flow and heat transfer occurring in an oscillating turbulent pipe flow. But most of investigations (Zhao and Cheng 1998a, b;Baird et al 1966;Liao and Wang 1985;Mamayev et al 1976;Gbadebo et al 1999;Habib et al 1999Habib et al , 2004Havemann and Rao 1954) have been focused on the experimental investigations.…”