Efficient waste heat recovery system for diesel engines using nano-enhanced phase change materials. (December 2021)

• Record Type: Journal Article
• Authors: Soliman, Ahmed Saad; Zhu, Shuping; Xu, Li; Dong, Junguo; Cheng, Ping
• Is Part Of: Case studies in thermal engineering. Volume 28(2021)
• Publication Date: 2021-12
• Subjects: Phase change materials -- Nanoparticles -- Turbulent flow -- Plate heat exchanger -- Heat recovery; Heat engineering -- Case studies -- Periodicals; 621.40205
• DOI: 10.1016/j.csite.2021.101390
• Languages: English
• ISSNs: 2214-157X

Abstract

Abstract: Cold start is one of the most difficult combustion phases of a diesel engine; and a large percentage of pollutants are produced during this period. Therefore, the present study focuses on proposing a numerical investigation of a novel design of an air preheating system to warm up the engine intake air at ambient air temperatures of 273 and 268 K. The preheating system consists of nano-enhanced phase change materials (NEPCM) housed in a plate heat exchanger. A comprehensive thermal model was developed and validated using experimental data from the literature. The model couples the transient turbulent fluid flow of the engine exhaust gases with the melting and solidification processes in the NEPCM domain. The effect of nanoparticle type, nanoparticle weight fraction, engine rotational speed, and ambient temperature were investigated. At 2000 rpm, the charging time was reduced by 34.88%, 30.23%, and 25.58% when using 5 w.t% of SiO2, Al2 O3, and CuO nanoparticles, respectively. During the discharging process, in less than 1 min, the cold intake air can be heated from ambient temperatures of 273 and 268 K to 301.8 and 300.6 K, respectively.