Experimental Study On Flow And Heat Transfer In Porous Media Of PAM Aqueous Solution

With cationic and anionic polyacrylamide aqueous solutions as experimental object, the experiment studied the effect of mass concentration, shear rate and temperature on the rheological properties of polyacrylamide aqueous solution. Experiment results indicated that the apparent viscosity of PAM solution increased linearly with increasing concentration linearly at a concentration of0.5-2.Og/L; the apparent viscosity decreased with the increasing of shear rate and temperature. With the changing of temperature and concentration, the flow behavior index n and consistency coefficient K behave similar to power-law fluid. Considering the combined effects of temperature and concentration, the experiment fitted an equation of the apparent viscosity with the regard of concentration and temperature. Through the measurement of viscoelasticity of PAM solution which was found that compared with elasticity, the viscosity of PAM solution is greater.The experiment on flow and heat transfer in porous media which is filled with copper ball particles used water and PAM aqueous solution as experimental fluid. The flow experiment found that in the double logarithmic coordinate system, the friction coefficient decreased linearly with the increasing of Reynolds Number when its value is lower. With same Reynolds Number, the ascending of temperature will lead to the increase of the corresponding friction coefficient for PAM aqueous solution of the same concentration. Temperature was kept stable and when the concentration of PAM aqueous solution is higher the critical Reynolds number for the transition from Darcy flow to transition flow is lower.Copper heater maintained constant heat flux for the porous media. Heat transfer experiment changed the fluid inlet velocity and the concentration of PAM solution to study the effect of power law rheological parameter on convective heat transfer coefficient. The experiment results indicated that the local convection heat transfer coefficient of water and PAM solution increased with the lifting flow rate when the inlet fluid temperature was kept steadily and it also states that flow rate is an important parameter for enhancing convective heat transfer properties in porous media. Comparing with the hx-x/De curve of water and PAM solution in porous media channel which found that entrance segment of water is shorter than PAM solution. Soon after entering the porous media channel water flow fully developed thermally. After a relatively long distance flow PAM solution will enter the heat fully developed stage. The experiment studied PAM solution of different concentrations and the results indicated that convective heat transfer coefficient became lower if the PAM solution’s value of n is smaller. If PAM solution’s value of n is larger, the impact of increasing the flow rate for enhancing convection heat transfer is more obvious.