NUMERICAL AND EXPERIMENTAL INVESTIGATION OF USING INNER LONGITUDINAL FINS IN A RECTANGULAR ENCAPSULATION ON THE PCM MELTING BEHAVIORS

الملخص

In this work, the effect of using inner longitudinal fins in a rectangular encapsulation on the PCM (paraffin wax) melting process was studied numerically and experimentally. An enthalpy transformation method was used in the numerical solution to transfer the equation of energy into a nonlinear equation with a single dependent variable H (enthalpy) by using FORTRAN (F90) program. The discretization of energy equation with phase change problem was solved in three dimensions by using the control-volume finite-difference. A comparative study was satisfactory made between the numerical results of the enthalpy method and the experimental results with approximation ratio (10%) along the test time (90) minute. The experimental results indicated that when using inner longitudinal fins in the same rectangular encapsulations led to decrease absorber surface temperature by 10 oC. This is because part of heat energy was injected deeply in the paraffin wax by the fins. This led to accelerate melting of PCM (paraffin wax) by about 12 min in section A which is under the effect of one fin, at a distance 3 cm from the heat absorber surface. While, at section B, where two longitudinal fins have effect, melting is decelerated by about 12 min.