Thermal stress analysis for exhaust heat exchanger

Abstract

Thermal stress induced in an object or structural member by restraint against movement is required to accommodate temperature changes. In this paper, the thermal stress and deformation of the exhaust heat exchanger on board a ship is analysed. The flow and temperature distributions of exhaust heat exchanger are conducted in ANSYS Static Structural by the coupled analysis of fluid and solid zones. According to the numerical analysis it is found that the thermal stress is increasing non-linearly with the increase of inlet sea water temperature. By increasing inlet sea water temperature will increase thermal stress. The result indicates that the maximum stress is equal to 479 MPa which is exceed the yield stress. Therefore, current heat exchanger being used is insufficient in design. By varying the different sea water inlet temperature and sea water inlet pressure at allowable limit still shows that maximum Von Misses Stress for current design is exceeding yield stress. The new design is proposed by increasing of thickness plate from 2mm to 3mm and proven to produce maximum Von Misses Stress below the yield stress which is equal to 245MPa. Percentage area for total thermal stress is also much lower compare to current design.