Publications de John Richard Thome

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Three micro-evaporator cooling cycles, one with a pump, one with a compressor and a hybrid of the two together, are proposed for cooling a computer blade server. The hybrid cycle is characterized by the interchangeability between the first two cycles, wher ...

An extensive database has been collected for the evaporation of two hydrofluorocarbon refrigerants (HFC- 134a and the zeotropic mixture HFC- 407C) and the natural refrigerant ammonia (R-717). A model to predict the onset of nucleate boiling has been successfully developed to differentiate pure convective evaporation from mixed convective and nucleate boiling heat transfer during horizontal evaporation inside a horizontal tube of 14mm I.D. The analysis of the Stratified, Stratified-Wavy and mainly Annular fl

Experimental studies were performed to investigate the flow patterns of liquid films of R-134a on vertical arrays of horizontal tubes under adiabatic test conditions at room temperature and during condensation at a saturation temperature of 304 K. Three ar ...

Multi-microchannel evaporators are often used to cool down electronic devices subjected to continuous heat load variations. However, so far, rare studies have addressed the transient flow boiling local heat transfer data occurring in such applications. The ...

A 3D ALE Finite Element Method is developed to study two-phase flow phenomena using a new discretization method to compute the surface tension forces. The computational method is based on the Arbitrary Lagrangian-Eulerian formulation (ALE) and the Finite E ...

This part of the paper presents the current experimental flow boiling heat transfer and CHF data acquired for R134a, R236fa and R245fa in single, horizontal channels of 1.03, 2.20 and 3.04 mm diameters over a range of experimental conditions. The aim of th ...

The purpose of this literature review is to compare different cooling technologies currently in development in research laboratories that are competing to solve the challenge of cooling the next generation of high heat flux computer chips. Today, most deve ...

In tune with the falling film evaporation heat transfer test results described in Part 1, flow visualization of the boiling process and intertube flow mode transitions from droplet to column and sheet flows have been observed, and the onset of dryout resul ...

The pulsating nature of a closed loop pulsating heat pipe (CLPHP) makes the prediction of its thermal-hydraulic performance extremely challenging. Unfortunately, the design of CLPHPs is still quite an empirical process, requiring testing of many prototypes ...

Infrared (IR) thermography was used to measure the local heat transfer coefficients within two plate heat exchanger geometries. The chevron patterns were machined into polycarbonate and IR transparent calcium fluoride plates, both of which were electricall ...

Gravity-driven cooling systems employing microchannel flow boiling can become a scalable and viable long term solution for the cooling of datacenter servers. In order to design this emerging type of cooling system, a new dynamic simulation tool using inter ...

A micro particle shadow velocimetry (mu PSV) system based on back-lit illumination and forward scatter observation of light from non-fluorescent particles has been developed. Relatively high luminous efficiencies and particle image contrasts were achieved ...

The current paper presents new operational maps for several different multi-microchannel evaporators, with and without any inlet restrictions (micro-orifices), for the two-phase flow of refrigerants R245fa, R236fa, and R1234ze(E). The test fluids flowed in ...

New correlations predicting the local boiling heat transfer coefficients for vertical flow over a tube bundle have been developed. These correlations were developed for three different classes of tubes: smooth, low-finned, and Turbo-BII HP. These correlati ...

This study focuses on the application of infra-red thermography to visualise the heat transfer dynamics of diabatic flows in multi-microchannels etched into silicon wafers. The 100 parallel channels were 50 micron wide, 100 microns deep, and with a pitch of 50 microns. The length of the channels was 10mm, and was limited by transverse inlet and outlet slits. A copper manifold was used to provide and remove fluid from the test section. This manifold was also designed to provide optical access to both the top

Micro particle shadow velocimetry is used to study the flow of water through microcircular sudden expansions of ratios e = 1.51 and e = 1.96 for inlet Reynolds numbers Re (d) < 120. Such flows give rise to annular vortices, trapped downstream of the expans ...

New experimental flow boiling heat transfer results averaged along a very low thermal conductivity polyimide channel are presented. The experimental setup consists of a horizontal, 285 mm-long, 2.689 mm inner diameter polyimide tube, heated by a counter-cu ...

Many parameters influence the falling-film evaporation process and, despite numerous studies, the basic mechanisms remain only partially clear, making the prediction of heat transfer still mainly an empirical process. The most important thermal design para ...

This paper discusses the effect of diameter on both flow boiling heat transfer and transition from macro to microchannel evaporation. A recently proposed three-zone flow boiling model based on evaporation of elongated bubbles in microchannels is briefly de ...

John Richard Thome

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Cooling of microprocessors with micro-evaporation: A novel two-phase cooling cycle

An Onset of Nucleate Boiling Criterion for Horizontal Flow Boiling

Visualization of R-134a Flowing on Tube Arrays with Plain and Enhanced Surfaces under Adiabatic and Condensing Conditions

Transient Data Processing of Flow Boiling Local Heat Transfer in a Multi-Microchannel Evaporator Under a Heat Flux Disturbance

A 3D moving mesh Finite Element Method for two-phase flows

Macro-to-microchannel transition in two-phase flow: Part 2-Flow boiling heat transfer and critical heat flux

State of the Art of High Heat Flux Cooling Technologies

Falling Films on Horizontal Tubes with R-134a, Part II: Flow Visualization, Onset of Dryout and Heat Transfer Predictions

Numerical Simulations of Pulsating Heat Pipes, Part 1: Modeling

Boiling heat transfer and two-phase pressure drops within compact plate heat exchangers: Experiments and flow visualizations

Two-phase mini-thermosyphon electronics cooling: Dynamic modeling, experimental validation and application to 2U servers

New Flow Boiling Heat Transfer Model and Flow Pattern Map for Carbon Dioxide Evaporating inside Tubes

A micro particle shadow velocimetry (mu PSV) technique to measure flows in microchannels

Two-phase flow operational maps for multi-microchannel evaporators

Prediction of Local Bundle Boiling Heat Transfer Coefficients: Pure Refrigerant Boiling on Plain, Low Fin and Turbo-BII HP Tube Bundles

Experimental investigation of diabatic flow in microchannels using infra-red thermography

Sudden expansions in circular microchannels: flow dynamics and pressure drop

Experimental flow boiling heat transfer in a small polyimide channel

Falling-Film Evaporation On Tube Bundle With Plain And Enhanced Tubes-Part Ii: New Prediction Methods

Evaporation in Microchannels: Influence of the Channel Diameter on Heat Transfer