Experimental study of heat transfer and pressure drop in micro-channel based heat sinks with tip clearance

Abstract

ARTICLE INFO ABSTRACT Keywords:Micro-heat sink Tip clearance Pressure dropThis article presents an experimental study on the optimisation of micro-heat sink configurations when both thermal effects and pressure drop are accounted fon The interest of the latter is that the practical engineering viability of some of these systems also depends on the required pumping power. The working ñuid was water and, according to typical power dissipation and system size requirements, the considered ñuid regime was either laminar or transitional, and not fully developed from the hydrodynamics point of view. Five configurations were considered: a reference geometry (selected for comparison purposes) made up of square section micro-channels, and four alternative configurations that involved the presence of a variable tip clearance in the design. The performance of the different configurations was compared with regard to both cooling efficiency and pressure drop. Finally, we also provide some practical guidelines for the engineering design of these types of systems.

Experimental and numerical study on the flow topology of finned heat sinks with tip clearance

“…Re for these volume flow rates and configuration CO (Re was based on the hydraulic diameter and average velocity at the channels cross-section) are also shown in Table 1. These Re are similar to those used in Reyes et al [10]. Ql to Q3 are in the laminar regime while Q4 could be considered to be close the beginning of the transitional regime.…”

“…These percentages were similar to those used in Ref. [10]. To homogenize the flow in the upstream stagnation chamber, a plastic honeycomb (manufactured with a 3D printer) and a series of five grids framed into a single piece were inserted right downstream of the inlet flow lines.…”

“…Additionally, a fourth computational domain, corresponding to a device with a tip clearance of 20 mm (200% of the fin height) also analyzed in Ref. [10], named con configuration C3, was simulated. Neither the grid nor the honeycomb were modeled in the computational domains that made up the matrix of cases to be analyzed.…”

“…To illustrate the details of the flow field, Fig. 13 shows, first, the dimensionless modulus of the transverse velocity defined as: \v*\ [(u y y + (u z yfl2 (10) for the four configurations CO to C4 at the same flow rate Q4 in section So (the inlet section of the channels, see Fig. 13, In each subplot of Fig.…”

“…More recently, Reyes et al [10] carried out an experimental study on the effects of tip clearance on a micro channel based heat sink. The authors considered three different values for the clearance height and compared it to a reference case with no clearance present.…”