Studies on diesel engine exhaust gas for waste heat recovery through triple pipe heat exchanger using different tubes

Abstract

newline A heat exchanger is a device which is designed for efficient heat transfer from one medium to other. The demand for high efficiency heat exchangers has been driven by energy and material saving requirements as well as environmental challenges in the industry. The Waste heat has generated by way of fuel combustion process. It is dumped into the environment and not reused for useful and economic purposes. The present research has studied the waste heat recovery from diesel engine exhaust using TPHE with variant intermediate tube geometries under different mass flow rates and different temperatures by numerically. By validating the CFD results, the dimpled tube achieves a better heat transfer rate, skin friction coefficient and effectiveness than other tubes comparatively. For experiment, the dimpled tube has tested under various fluid flow configurations and engine speed 1500rpm at 5 minutes periodically. The maximum performance attained for speed of 1500 rpm at counter-current flow (Type A) condition. The dimpled tube achieves the effectiveness up to 76.09% for 100% load by CFD whereas69.90% by experiment for co current flow. The maximum energy could be obtained from 1232000 to 1844000 kW-hr based on applying loads for engine lifetimes of 100000 hrs. Hence, the recovered heat energy can be utilized for boilers, steam generators, pre heaters, evaporation, Heating, Cooling etc.