Publications de John Richard Thome

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An experimental study was completed on the heat transfer induced by a single elongated vapor bubble rising in vertical, upward, co-current flow at various accelerations. The bubble shape and behavior were also studied under those conditions. Tests were con ...

This paper presents a fundamental study of the flow dynamics and heat transfer induced by a slug flow under saturated flow boiling in a circular microchannel. Numerical simulations are carried out by utilizing the commercial CFD solver ANSYS FLUENT v. 14.5, with its built-in volume of fluid (VOF) method to advect the interface, which was improved here by implementing self-developed functions to model the phase change and the surface tension force. A continuous stream of bubbles is generated (by additional u

The heat transfer performance of commercially produced micro-enhanced tubes with and without a nanocoating was investigated under pool boiling of saturated refrigerant. These multiscale enhancements were on the outside of 19 mm horizontal copper tubes heat ...

In this paper, I will present an abridged overview of what is presented in my keynote lecture. I will recount some of the initial history of microchannel two-phase flow and boiling work by others that enticed me to join into the development of this field a ...

Over the years, much research has been conducted on two-phase flows in straight tubes because these tend, in length, to be predominant in two-phase systems. However, two-phase heat exchangers can also have singularity elements, where the most common type i ...

The upward flow boiling experiments were carried out in a flat aluminum extruded multiport tube, which is composed of 7 parallel rectangular channels (1.1 mm × 2.1 mm) with hydraulic diameter of 1.4 mm. Two refrigerants, R245fa and R1234ze, the latter a recent environmentally safe refrigerant proposed as a potential replacement for R134a, were tested. A new hot water heating technique that accounts for either uniform or non-uniform local heat flux distribution along the channel was developed to obtain and r

Three-dimensional (3D) stacking of integrated circuit (IC) dies by vertical integration increases system density and package functionality. The vertical integration of IC dies by area-array Through-Silicon-Vias (TSVs) reduces the length of global interconn ...

This work proposes a novel physics-based model for the fluid mechanics and heat transfer associated with slug flow boiling in horizontal circular microchannels to update the widely used three-zone model of Thome et al. (2004). The heat transfer model has a ...

An experimental study on flow boiling pressure drop and heat transfer of a new environmentally friendly refrigerant R1233zd(E), in a parallel multi-microchannel evaporator was carried out. The silicon microchannels evaporator was 10 mm long and 10 mm wide, ...

Experimental flow boiling heat transfer results are presented for horizontal 1.0 and 2.2 mm I. D. (internal diameter) stainless steel tubes for tests with R1234ze(E), a new refrigerant developed as a substitute for R134a with a much lower global warming po ...

New predictive methods for falling film condensation on vertical arrays of horizontal tubes using different refrigerants are proposed, based on visual observations revealing that condensate is slung off the array of tubes sideways and significantly affects ...

The main objective of this paper is to utilize an improved version of the simulator presented at InterPACK 2017 to design a thermosyphon system for energy-efficient heat removal from 2-U servers used in high-power datacenters. Currently, between 25% and 45 ...

A survey of the most recent work aimed at physically characterizing local heat transfer in flow boiling in microchannels is presented. This includes recent experimental work, new flow boiling prediction methods, and numerical simulations of microchannel sl ...

In this work flow visualizations and measurements are made and analyzed to identify flow regime transitions, slug-to-intermittent, intermittent-to-annular and the dry-out inception, during the flow boiling of CO2 in a horizontal smooth tube of 6.00 mm of i ...

In two-phase systems there are many singularities in piping systems, one of which in particular are U-bends (also called 180 degrees return bends or U-tubes) found very often in air conditioning coils, refrigerant systems, etc. Contrary to the literature c ...

Experimental and numerical studies are performed to characterise the dynamics of isolated confined air bubbles in laminar fully developed liquid flows within channels of diameters d = 0.5 mm and d = 1 mm. Water and glycerol are used as the continuous liqui ...

Numerous characteristic trends and effects have been observed in published studies on two-phase micro-channel boiling heat transfer. While macro-scale flow boiling heat transfer may be decomposed into nucleate and convective boiling contributions, at the m ...

This paper advances the work presented at ITHERM 2020 where a novel passive two-phase technology was introduced for more efficient cooling of datacenters compared to air-based cooling solutions (e.g. In-Room, In-Row, etc.). The proposed hybrid two-phase co ...

Few experimental test data are available for evaporation of ammonia inside tubes and numerous new data have been measured and presented here. An improved approach to the prediction of flow boiling heat transfer in horizontal tubes has been proposed through the study of each flow pattern separately, incorporating a new criterion defining the onset of nucleate boiling as a function of the critical convective heat transfer coefficient representative of the location where nucleate boiling might occur. A new fun

This study is focused on the experimental characterization of two-phase heat transfer performance and pressure drops within an ultracompact heat exchanger (UCHE) suitable for electronics cooling applications. In this specific work, the UCHE prototype is an ...

John Richard Thome

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A study of gravitational effects on single elongated vapor bubbles

Computational Study of Saturated Flow Boiling Within a Microchannel in the Slug Flow Regime

Heat transfer of uncoated and nanostructure coated commercially micro-enhanced refrigeration tubes under pool boiling conditions

Micro-Two-Phase Electronics Cooling: Finally on Its Way

Two-phase frictional pressure drops in U-bends and contiguous straight tubes for different refrigerants, orientations, tube, and bend diameters: Part 1. Experimental results (RP-1444)

Experimental study on flow boiling heat transfer of multiport tubes with R245fa and R1234ze(E)

Integration of Intra Chip Stack Fluidic Cooling using Thin-Layer Solder Bonding

An updated three-zone heat transfer model for slug flow boiling in microchannels

Experimental investigation on flow boiling pressure drop and heat transfer of R1233zd(E) in a multi-microchannel evaporator

Flow Boiling Characteristics for R1234ze(E) in 1.0 and 2.2 mm Circular Channels

Film Condensation of R-134a and R-236fa, Part 1: Experimental Results and Predictive Correlation for Single-Row Condensation on Enhanced Tubes

Design Of Passive Two-Phase Thermosyphons For Server Cooling

Proposed models, ongoing experiments, and latest numerical simulations of microchannel two-phase flow boiling

Flow pattern maps for convective boiling of CO2 and R410A in a horizontal smooth tube: Experiments and new correlations analyzing the effect of the reduced pressure

Two-phase flow patterns in U-bends and their contiguous straight tubes for different orientations, tube and bend diameters

Dynamics of isolated confined air bubbles in liquid flows through circular microchannels: an experimental and numerical study

Mechanisms of Boiling in Micro-Channels: Critical Assessment

Hybrid Two-Phase Cooling Technology For Next-Generation Servers: Thermal Performance Analysis

Evaporation of Refrigerants in a Horizontal tube: An Improved Flow Pattern Dependent Heat Transfer Model Compared to Ammonia Data

Ultra-Compact Microscale Heat Exchanger for Advanced Thermal Management in Data Centers