Avaliação da degradação de um fluido refrigerador usado em intercoolers de automóveis

November 29, 2022

This dissertation, carried out in collaboration with JDeus, had as main objective to detect potential changes in the properties of the coolant used, ethylene glycol-water 50/50% vol, due to its degradation during use and the possible consequences for heat transfer. The experimental work carried out was based on the characterization of the flow of four samples of ethylene glycol in a smooth tube with an internal diameter of 4.5 mm and a length of 1.515 m. The first sample is an unused ethylene glycol and the remaining three are fluids aged at 150°C for 500h, 1000h, and 1500h. For the four fluids, several flow rates were analyzed from the laminar to turbulent regime, doing three test runs with similar flow rate evolution with variable heat fluxes. The flow rates were controlled by an electromagnetic pump. The heat fluxes were imposed by Joule effect in the pipe after current induction in the test section. For analysis, values of flow rate, imposed heat flux, temperatures and pressure drop along the test section were collected in order to characterize the observed hydrodynamic and thermal processes. It was concluded that there is degradation of ethylene glycol impacting the heat transmission process. The Nusselt number decreased with increasing number of aging hours. The largest drop was recorded between the 500h and 1000h samples. The aging of the fluid has a practically negligible effect on the friction factor with small variations in values. In the thermal performance there were losses of 30%.

Authors in the community:

• 

  D

  Duarte Miguel Niza Meira Jesus

  ist425839

Supervisors of this institution:

• 

  A

  António Luís Nobre Moreira

  ist12089

mechanical-engineering - Mechanical engineering

por - Portuguese

Instituto Superior Técnico