Fabrication of Micro-Patterned Surface for Pool-boiling Enhancement by Using Powder Injection Molding Process.

Hanlyun Cho,Jungho Lee,Seung Mun You,Dani Fadda,Juan Godinez,Jun Sae Han,Seong Jin Park

doi:10.3390/ma12030507

Abstract

In this study, two kinds of copper micro-patterned surfaces with different heights were fabricated by using a powder injection molding (PIM) process. The micro-pattern’s size was 100 μm, and the gap size was 50 μm. The short micro-pattern’s height was 100 μm, and the height of the tall one was 380 μm. A copper powder and wax-polymer-based binder system was used to fabricate the micro-patterned surfaces. The critical heat flux (CHF) and heat transfer coefficient (HTC) during pool-boiling tests were measured with the micro-patterned surfaces and a reference plain copper surface. The CHF of short and tall micro-patterned surfaces were 1434 and 1444 kW/m2, respectively, and the plain copper surface’s CHF was 1191 kW/m2. The HTC of the plain copper surface and the PIM surface with short and tall micro-patterned surfaces were similar in value up to a heat flux 1000 kW/m2. Beyond that value, the plain surface quickly reached its CHF, while the HTC of the short micro-patterned surface achieved higher values than that of the tall micro-patterned surface. At CHF, the maximum values of HTC for the short micro-pattern, tall micro-pattern, and the plain copper surface were 68, 58, and 57 kW/m2 K.

Highlights

The surface of a reactor in a nuclear power plant requires highly effective cooling
Of particular note is the tall-patterned surface, which appears fully wetted within kW/m2 is shown in Figure 9 for the plain copper surface, the short micro-patterned surface, and the
Is partially due to the reduced contact angle of the powder injection molded (PIMed) material and partially due to the patterned surface behaving as a pin wall which allows water to penetrate between the pins during the measurements

Summary

Introduction

The surface of a reactor in a nuclear power plant requires highly effective cooling. Achieving effective boiling heat transfer is required in order to improve the nuclear power plant’s safety and prevent damage that can occur due to excessive heat. Research in pool-boiling heat transfer can be directly used in this cooling application, among numerous other applications. Representative quantities for pool-boiling heat transfer are the critical heat flux (CHF) and the heat transfer coefficient (HTC) [2]. CHF is the upper limit of the nucleate boiling regime where a vapor film blankets the heating surface and causes a significant reduction of the HTC. When the applied heat flux increases towards CHF, vapor generation prevents the surface

Methods

Results

Discussion

Conclusion