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In this study, performance of a flat plate solar collector operating in conjunction with a closed-loop pulsating heat pipe is investigated experimentally. The experiments were carried out in Yazd, Iran. The experimental setup consisted of a flat plate solar collector, pulsating heat pipe, and a tank. The pulsating heat pipe's evaporator is located inside the flat plate collector. In order to investigate the effect of the evaporator length on the efficiency of the system, three different length collectors are manufactured in the evaporating section. In addition, the effects of the pulsating heat pipe filling ratio, inclination angle, and flow rate are investigated for each collector separately. Although the increase in the length of the evaporator adversely affects the convectional heat transfer, the results do not show a noticeable deterioration in the performance of the flat plate solar collector. The optimum value of the filling ratio of the pulsating heat pipe in all three devices was measured at 30%, regardless of the length of the evaporator. Finally by varying the inclination angle to maximize the value of solar radiation, the study determined that the optimal tilt angle occurred at 20°.

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SUMMARYAn improved incompressible smoothed particle hydrodynamics (ISPH) method is presented, which employs first-order consistent discretization schemes both for the first-order and second-order spatial derivatives. A recently introduced wall boundary condition is implemented in the context of ISPH method, which does not rely on using dummy particles and, as a result, can be applied more efficiently and with less computational complexity. To assess the accuracy and computational efficiency of this improved ISPH method, a number of two-dimensional incompressible laminar internal flow benchmark problems are solved and the results are compared with available analytical solutions and numerical data. It is shown that using smaller smoothing lengths, the proposed method can provide desirable accuracies with relatively less computational cost for two-dimensional problems.