Experimental Study of Single Phase Heat Transfer and Pressure Loss in a Spiraling Radial Inflow Microchannel Heat Sink

Abstract

This paper presents an experimental study of the heat transfer and pressure drop characteristics of a single phase high heat flux microchannel cooling system with spiraling radial inflow. The heat sink provides enhanced heat transfer with a simple inlet and outlet design while providing uniform flow distribution. The system is heated from one conducting wall made of copper and uses water as a working fluid. The microchannel has a 1 cm radius and a 300 μm gap height. Experimental results show, on average, a 76% larger pressure drop compared to an analytic model for laminar flow in a parallel disk system with spiral radial inflow. The mean heat transfer coefficients measured are up to four times the heat transfer coefficient for unidirectional laminar fully developed flow between parallel plates with the same gap height. Flow visualization studies indicate the presence of secondary flows and the onset of turbulence at higher flow rates. Combined with the thermally developing nature of the flow, these characteristics lead to enhanced heat transfer coefficients relative to the laminar parallel plate values. Another beneficial feature of this device, for high heat flux cooling applications, is that the thermal gradients on the surface are small. The average variation in surface temperature is 18% of the total bulk fluid temperature gain across the device. The system showed promising cooling characteristics for electronics and concentrated photovoltaics applications with a heat flux of 113 W/cm2 at a surface temperature of 77 °C and a ratio of pumping power to heat rate of 0.03%.

Spatially-selective cooling by liquid jet impinging orthogonally on a wettability-patterned surface

“…Dissipation of heat from small areas is a critical requirement in many engineering applications, such as heat treatment of metal parts [1], thermal management in electronic and photonic devices [2], power devices [3], electric vehicles [3,4], advanced military avionics [3], nuclear reactors [5], or even photovoltaic cells [6]. In many applications, air has been used as a coolant due to the associated low cost.…”

Heat transfer augmentation in a radial curved microchannel

“…Comparison between experimental results 25 and numerical results of the (a) effect of Nusselt number with Reynolds number and (b) effect of pressure drop with Reynolds number.…”

“…However, the boiling heat coefficient decreased with an increase in the aspect ratio of the channel but the same increased with an increase in the mass flow rate. Maritza et al 25 conducted experiments on spiraling microchannels with a circumferential single inlet and central vertical outlet to study the pressure drop and thermal characteristics for high heat flux applications. Their model showed small thermal gradients on the surface with 18% variation in the average surface temperature of the total change in bulk fluid temperature from the inlet to the outlet.…”

Optimal Structural Design of a Heat Sink With Laminar Single-Phase Flow Using Computational Fluid Dynamics-Based Multi-Objective Genetic Algorithm

“…When optimizing a heat transfer unit or a system, the flow resistance often has an increase with the enhancement of heat transfer [6][7][8][9][10]. In general, the micro/minichannel offers a large heat transfer area and a high convective heat transfer coefficient, while high pumping power is also required for driving the fluid.…”