MICROCHANNEL CONJUGATE HEAT TRANSFER MODELING USING LATTICE BOLTZMANN METHOD WITH A NEW DISCRETIZATION STRATEGY

Author(s)

Martins, Ivan T. ; Gomez, Luben C.

• Document type: Journal article
• Source: JOURNAL OF ENHANCED HEAT TRANSFER; v. 29, n. 3, p. 24-pg., 2022-01-01.

Abstract

In heat exchangers of refrigeration systems, it is common to use materials (fluids and solids) with thermal and viscosity properties differing by some orders of magnitude. In order to simulate thermal flows in these systems with the Lattice Boltzmann Method, it is necessary to set different relaxation times for momentum and energy conservation equations. In this paper, it is proposed to use different temporal and spatial discretizations for solving each conservation equation. This means that different scales are applied to calculate each distribution function. First, a benchmark thermal flow problem is studied, in order to validate the functionality of the proposed method. Then, a real problem of a thermal flow in a microchannel is solved. This microchannel is made of silicon, considering first water as the refrigerating fluid and second, R123. The proposed strategy is tested by comparing the obtained results for microchannel temperature and velocity fields with simulated results from COMSOL software, showing good accuracy. Numerical solutions of Nusselt number for a microchannel with water were also compared with data from several literature sources, providing physically correct results which confirm the literature data trends. These comparisons indicate that the new proposed simulation procedure is adequate and improves the use of Lattice Boltzmann Method to simulate microchannels flows considering the conjugate heat transfer effects. (AU)

• FAPESP's process: 19/21022-9 - Study of lattice Boltzmann Method for numerical simulation of hydrodynamic and thermal processes in microchannels
• Grantee: Ivan Talão Martins
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• FAPESP's process: 16/09509-1 - Phase change heat transfer processes of high performance applied to solar energy recovery
• Grantee: Gherhardt Ribatski
• Support Opportunities: Research Projects - Thematic Grants