Investigation of Effects of Vibrations on Nanofluid-Filled Pulsating Heat Pipe for Efficient Electric Vehicle Battery Thermal Management

Abstract

Pulsating heat pipes are effective heat transfer devices that can provide passive thermal management solutions for electronics and electric vehicle batteries. In this work, the thermal performance and startup characteristics of a specially designed multiplanar PHP are investigated. Hybrid CuO + Fe₃O₄-water (2 wt. %) nanofluid is used as the working fluid in pulsating heat pipes. The improvement in cooling performance is assessed and compared to that of water. In mobile applications of PHPs like electric vehicle battery thermal management, components are regularly exposed to the vibrations induced by vehicle systems, and hence working characteristics of PHP under vibrations need a detailed investigation. Hence, this work also explores the effect of vibrations (~ 30 Hz) on the thermal performance of pulsating heat pipe to study its feasibility for electric vehicle battery thermal management application. The findings of this work show that with nanofluids, the startup temperature of pulsating heat pipe reduces marginally, and thermal resistance decreases by a maximum of 13.49%. Results also show that under vibrations, pulsating heat pipe shows significantly low startup temperature and reduced thermal resistance. A maximum decrease in thermal resistance under vibrations is observed at 45° pulsating heat pipe inclination; it is 11.40% for water and 8.05% for nanofluid. Also, a regression analysis is conducted to formulate a correlation to predict the thermal resistance of pulsating heat pipes based on different input parameters. The mean absolute percentage deviation (MAPD) between the predicted and experimental data is observed as 4.67% for the correlation based on current study data.