Effect of pulsating inlet flow on heat and fluid flow

In this study, the effect of pulsating inlet flow in a pipe on flow and heat transfer was investigated experimentally, analytically and numerically. Designing an experimental set-up to enable to the pulsating flow, hydrodynamical and thermal measurements for various working conditions were conducted. In the analytical study, the velocity, pressure and temperature distributions were obtained for a two dimensional, laminar, incompressible fluid flow and heat transfer in a cylindrical pipe whose walls were subjected to a constant heat flux by solving governing equations under the corresponding boundary conditions. In the numerical study, FLUENT, a commercial CFD package program based on the control volume method, was used. The comprehensive parametrical simulations were conducted for the same problem. In the following, velocity, pressure and temperature distributions in the thermally developing region and radial velocity and temperature distribution in fully developed region were predicted for various working conditions. In hydrodynamical study, it is aimed at obtaining the effect of flow mechanism in pulsating flow (mainly frequency and amplitude) on the hydrodynamic development length and the friction coefficient. In addition, it was also determined that how frequency affected phase difference between pressure and velocity time-variations. In the thermal analysis, effect of pulsation on heat transfer for which contradictory findings existed in the literature was investigated for a quite wide range of working parameters. It is shown that freq. and amplitude both for the pressure and piston-driven flows has a considerable effect on the hydrodynamical and thermal characteristics. Generally, a good agreement is observed among analytical, numerical and experimental results.