Implementation of metal-based microchannel heat exchangers in a microrefrigeration cycle, and numerical and experimental investigation of surface roughness effects on flow boiling

Download
2015
Jafari Khousheh Mehr, Rahim
A microscale vapor compression refrigeration cycle has been constructed for possible application in the thermal management of compact electronic components. The micro-evaporator and micro-condenser components have been fabricated using wire electron discharge machining and micromilling, respectively. Three microevaporators have been manufactured with different surface roughness for the experimental and numerical investigation of roughness effect on nucleate flow boiling in microchannels. In the numerical part of the study, two different techniques have been employed to simulate the evaporation in the microchannels. Firstly, the Arbitrary LagrangianEulerian Method is used to investigate the hydrodynamics and heat transfer vi characteristics of a vaporized elongated bubble, and two successive bubbles in a microtube. Then, phase-field method is utilized, uniquely, for the simulation of saturated and subcooled water boiling in the microchannels with different size of cavities as a preliminary model for the surface roughness. Manufacturing experiments with various process parameters have been conducted to create the different surface roughness values in the oxygen free copper microevaporator channels. In the experimental evaluation part, the hydrodynamics and heat transfer performance of the three microchannel evaporators of the same dimensions and different surface roughness have been compared at variously imposed heat fluxes and mass fluxes. R134a has been used as the refrigerant with saturation temperature of 10 & at mass fluxes of 85 and 200 kg/(m2Âs). The results demonstrated that roughness yields up to 45% enhancement in two-phase heat transfer coefficient at low to moderate heat flux values ranging from 0 to 48 W/cm2.

Suggestions

Heat dissipation from electronic packages on rotary platforms with the help of heat pipe networks
Çalışkan, Anıl; Tarı, İlker; Department of Mechanical Engineering (2015)
An electronics package on a rotary platform including two components with 600 W, one component with 350 W and one small component with 70 W heat dissipation rates (1620 W total heat load) is numerically and experimentally investigated under steady state conditions. In order to avoid rotary joints and to reduce the costs of design, maintenance and production, the thermal management solution for the heat dissipation is entirely placed on the rotary platform. The thermal management solution includes heat sinks...
Design, optimization and testing of micro-evaporator and micro-condenser components used in a miniature vapor compression refrigeration cycle
Türkakar, Göker; Okutucu Özyurt, Hanife Tuba; Department of Mechanical Engineering (2016)
This study aims to optimize the dimensions and operating conditions of two main components of a miniature vapor compression refrigeration cycle (MVCRC), evaporator and condenser by using entropy generation minimization (EGM). In addition, some performance tests are conducted on a MVCRC which is constructed based on the EGM analysis as long as the manufacturing constraints permit. R134a is used as the coolant. Entropy generation rate in the evaporator of the MVCRC is investigated under the effects of exit va...
Modeling of multidimensional heat transfer in a rectangular grooved heat pipe /
Odabaşı, Gülnihal; Dursunkaya, Zafer; Department of Mechanical Engineering (2014)
Heat pipes are generally preferred for electronics cooling application due to large heat transfer capacity in spite of small size. Micro heat pipes use small channels, whose dimension is on the order of micrometers, to generate necessary capillary action maintaining fluid flow for heat pipe operation. In the present study a flat micro heat pipe with rectangular cross section is analyzed numerically. A simplified axial fluid flow model is utilized to find liquid-vapor interface shape variation along the heat...
Investigation of flow and heat transfer behavior of integrated pin fin-aluminum foam heat sink
ŞAHİN, Yiğit Serkan; TOPRAK, Beytullah İsmet; SOLMAZ, İsmail; Bayer, Özgür (2023-01-01)
With the rapid development in the electronics industry, the thermal management of high power density elec-tronic products (HPDEPs) has become very important and requires innovative heat removal technologies. In this study, an integrated heat sink (IHS) fabricated by combining aluminum foam and pin-finned heat sink config-urations that are frequently used in the cooling of electronic products has been proposed as an effective solution for the thermal management of HPDEPs. The heat removal and pressure drop c...
Experimental investigation and 3D finite element prediction of the white layer thickness, heat affected zone, and surface roughness in EDM process
Shabgard, Mohammadreza; Oliaei, Samad Nadimi Bavil; Seyedzavvar, Mirsadegh; Najadebrahimi, Ahmad (2011-12-01)
An axisymmetric three-dimensional model or temperature distribution in the electrical discharge machining process has been developed using the finite element method to estimate the surface integrity characteristics of AISI H13 tool steel as workpiece. White layer thickness, depth of heat affected zone, and arithmetical mean roughness consisting of the studied surface integrity features on which the effect of process parameters, including pulse on-time and pulse current were investigated. Additionally, the e...
Citation Formats
R. Jafari Khousheh Mehr, “Implementation of metal-based microchannel heat exchangers in a microrefrigeration cycle, and numerical and experimental investigation of surface roughness effects on flow boiling,” Ph.D. - Doctoral Program, Middle East Technical University, 2015.