Numerical Simulation Of Convection Heat Transfer With Pulsating Flow And Spiral Flow In A Duct

Pulsating flow and spiral flow are familiar flowing forms, which are widely used in industry. As a kind of representative and non-linear evanescence flow, the measure of pulsating flow requests nicety and celerity.The available published data have been disputed and they often show conflicting results. These haven't adapted well to the wide using of industrial. As result of circumrotating, even circumfluence, the configuration of spiral (swirling) flow is very complex. The embedded study on characteristic of spiral (swirling) flow is very necessary. Pulsating and spiral (swirling) flow have prodigious effects on convective heat transfer. The means of former analytic and experimentation can't be satisfied for investigate requirements. This paper will study the simulation of flow and convective heat transfer with pulsating and spiral (swirling) flow.For pulsating flow, the convective heat transfer process through a slick duct (d=0.01m,l=3.0m) with constant temperature(330K) is simulated when the inlet velocity of water is periodical(U0= U0 [1+ Asin(2πfτ)], U0=0.25, 1.5m/s,A=0.1,0.2,0.3,0.5,0.8and f=0.05Hz,1Hz,2Hz,5Hz,10Hz).The effect of non-dimensional amplitude and frequency on the convection heat transfer coefficient, friction factor and temperature is analyzed. The results show that:(1) The pulsating flow at constant wall temperature can result in the fluctuation of the pressure, temperature, Nusselt number and the thickness of boundary layer around the non-pulsation flow. The larger non-dimensional amplitude and the smaller frequency are, the larger fluctuation will be. (2) The time- averaged values of pressure, temperature, Nusselt number, friction coefficient and the thickness of boundary layer in a cycle are equal to non-pulsation ones at the same Reynolds number. The convection heat transfer and the resistance between the Pulsating Flow and non-pulsation flow are the same.For spiral (swirling) flow, adopting local rise- spiral (swirling) installation, a slick duct (d=0.05m,l=15m) with constant temperature (330K), studies of differ oriented pipes (d=0.01m, 0.02m), flow and convective heat transfer of water under differ Reynolds numbers (2783~16997) have been progressed. The results show that:(1) The effect of spiral (swirling) flow for enhancement convective heat transfer is evident. In the velocity range of industrial heat transfer, convective heat transfer can be enhanced 8%~20%.With the increase of axes velocity or average Reynolds number, the enhancement increased. (2) Compared with non-spiral (swirling) flow, the velocity distributing of spiral (swirling)...