Waste Heat Recovery (WHR) of Diesel Engine Using Closed-Loop Pulsating Heat Pipe

In internal combustion engine, around 25–40% of energy is expelled through the exhaust gases into environment which causes pollution. So this energy should be recovered for other applications. This present work represents the study of the pulsating heat pipe (PHP) technique used for heating the air with the help of recovered heat from exhaust of the engine. The CLPHP is most effective, promising heat transfer device than the others, which uses the pulsating or oscillating actions of the working fluid for transferring heat. The performance of CLPHP basically depends on different parameters like filling ratio (F.R), internal diameter of the tube(D_i), cross section area of tube (A_c), heat input(Q_in), angle of inclination (θ), no of turns (N), working fluid, length of tube in evaporator and condenser section, etc. In this work, eight-loop PHP is made of copper material having ID = 3.2512 mm and OD = 4.7752 mm with water as working fluid. The experimental investigation is performed for different filling ratios (50, 60 and 70%) and at various heat inputs (715.98, 861.48, 935.41, 1004.96 and 1070.5 W) by varying the loads on engine. The result shows that for 50% filling ratio, overall thermal resistance is less and heat transfer coefficient value is more as compared to other filling ratios.