Heat transfer characteristics in impinging jet arrays

Abstract

Impinging jets have often been regarded as suitable fluid mechanisms for use in high heat flux micro heat exchangers. For cases where high heat fluxes are present over large areas, arrays of impinging jets are often used. In this paper, the array geometry to provide maximum heat transfer is determined by a parametric study on impinging jets arranged in both square and hexagonal arrays. Closely packed jet arrays are numerically modelled for a range of jet-to-surface distances, jet-to-jet spacings and jet velocities. The optimum array configuration is determined by comparison of the average surface Nusselt number. Results indicate that the average heat transfer increases as the spacing between jets decreases up to a critical point at which the heat transfer is sharply reduced. The flow characteristics affecting this critical distance for jet arrays are examined.

Keywords:

• Jet impingement
• jet array
• heat transfer
• numerical analysis