Publications by John Richard Thome

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The complexities of two-phase flow and falling-film evaporation on a tube bundle present important challenges in the design of heat exchangers and the understanding of the physical phenomena taking place. The development of structured surfaces to enhance n ...

We seek to study numerically two-phase flow phenomena with phase change through the finite-element method (FEM) and the arbitrary Lagrangian-Eulerian (ALE) framework. This method is based on the so-called one-fluid formulation; thus, only one set of equati ...

Carbon dioxide two-phase flow characteristics are different from those of conventional refrigerants, due to the CO2 particular thermodynamic and transport properties obtained by working at high reduced pressures. Moreover, the use of peculiar heat transfer ...

Due to the local pulsating/transient nature and complex thermal-hydraulic coupling of a closed loop pulsating heat pipe (CLPHP), there is a need to develop an effective simulation code capable to design and predict the local and overall thermal performance ...

Gravity-driven two-phase liquid cooling systems using flow boiling within micro-scale evaporators are becoming a game changing solution for electronics cooling. The optimization of the system's filling ratio can however become a challenging problem for a s ...

The pressure drops of external flow over enhanced tube bundles were experimentally obtained at both adiabatic and diabatic conditions using R-134a and R-236fa as test fluids. The tests were carried out at saturation temperatures of 5 and 15 degrees C, mass ...

The current study presents a one-dimensional model of confined coalescing bubble flow for the prediction of micro-channel convective boiling heat transfer. Coalescing bubble flow has recently been identified as one of the characteristic flow patterns to be ...

The two fluid model is used to simulate upward gas-liquid bubbly flow through a vertical conduit. Coalescence and breakup of bubbles have been accounted for by embedding the population balance technique in the two fluid model. The simulation enables one to ...

In the European project BRAINE, an extremely efficient passive thermosyphon cooling system was developed for a novel type of Edge MicroDataCenter (EMDC) with high heat fluxes to dissipate on individual computer cards and high heat dissipation rate per unit ...

An indirect method to identify the laminar to turbulent flow transition in shear-driven annular liquid films has been developed and used, together with literature measurements of the velocity profile, to approximately resolve the near wall structure in she ...

An improved two-phase flow pattern map is proposed for evaporation in horizontal tubes. The new map was developed based on flow pattern data for five different refrigerants covering a wide range of mass velocities and vapor qualities. The new map is valid for both adiabatic and diabatic (evaporating) flows and accurately identifies about 96% of the 702 data points. In addition, the new flow pattern map includes the prediciton of the onset of dryout at the top of the tube during evaporation inside horizontal

Flow boiling within microchannels has been explored intensively in the last decade due to their capability to remove high heat fluxes from microelectronic devices. However, the contribution of experiments to the understanding of the local features of the f ...

A comprehensive experimental campaign has been conducted to measure the local heat transfer coefficients during flow boiling of refrigerants in multi-microchannel evaporators. Two additional refrigerants (R245fa and R236fa) were tested in two silicon evapo ...

An experimental apparatus for evaluating carbon dioxide local heat transfer coefficients during flow boiling has been set up at University of Naples Federico II. In this paper, the local heat transfer coefficient measured is evaluated relative to the measu ...

This article is the first part of a study on flow boiling of R236fa and R245fa. This part presents pressure drop measurements obtained on a silicon multi-microchannel evaporator with 85 urn wide and 560 mu m high channels separated by 46 mu m wide fins. The 135 microchannels were 12.7 mm long. Dielectric refrigerants R236fa and R245fa were used as the evaporating test fluids. The inlet saturation temperature was maintained at 30.5 degrees C while the mass fluxes were varied from 499 to 1100 kg/m(2)s and the

This work presents an analytical investigation of two-phase pressure drops during evaporation in horizontal tubes. Based on a comprehensive state-of-the-art review and comparison with two-phase frictional pressure drop prediction methods, it is proven that ...

The classification of macroscale, mesoscale and microscale channels with respect to two-phase processes is still an open question. The main objective of this study focuses on investigating the macro-to-microscale transition during flow boiling in small sca ...

A boundary-fitted moving mesh scheme is presented for the simulation of two-phase flow in two-dimensional and axisymmetric geometries. The incompressible Navier-Stokes equations are solved using the finite element method, and the mini element is used to sa ...

A new heat transfer model for intube flow boiling in horizontal plain tubes is proposed that incorporates the effects of local two-phase flow patterns, flow stratification and partial dryout in annular flow. Significantly, the local peak in the heat transfer coefficient versus vapor quality can now be determined from the prediction of the location of onset of partial dryout in annular flow. The new method accurately predicts a large, new database of flow boiling data, and is perticularly better than existin

New trends in the microprocessor industry are leading not only to miniaturization and integration but also to increases in power dissipation rates which now require advanced cooling solutions to prevent thermal damage to the devices. Pulsating heat pipes ( ...

John Richard Thome

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Falling-Film Evaporation On Tube Bundle With Plain And Enhanced Tubes-Part I: Experimental Results

3D ALE Finite-Element Method for Two-Phase Flows With Phase Change

Influencing factors on flow boiling of carbon dioxide in enhanced tubes and comparison with correlations

Numerical Simulations of Pulsating Heat Pipes, Part 2: Comparison to Experimental Data

Role Of A Liquid Accumulator In A Passive Two-Phase Liquid Cooling System For Electronics: Experimental Analysis

Pressure drop data and prediction method for enhanced external boiling tube bundles with R-134a and R-236fa

A heat transfer model for evaporation of coalescing bubbles in micro-channel flow

Transition of Bubbly Flow in Vertical Tubes: New Criteria Through CFD Simulation

Thermal-Hydraulic Characterization of a Thermosyphon Cooling System for Highly Compact Edge MicroDataCenter

An indirect criterion for the laminar to turbulent flow transition in shear-driven annular liquid films

Flow Boiling in Horizontal Tubes. Part 1; Development of a Diabatic Two–Phase Flow Pattern Map

Numerical investigation of hydrodynamics and heat transfer of elongated bubbles during flow boiling in a microchannel

Local measurements and a new flow pattern based model for subcooled and saturated flow boiling heat transfer in multi-microchannel evaporators

A methodology to select the experimental plant instrumentation based on an a priori analysis of measurement errors and instrumentation cost

Two-phase flow of refrigerants in 85μm-wide multi-microchannels: Part I – Pressure drop

Flow pattern based two-phase frictional pressure drop model for horizontal tubes, Part II: New phenomenological model

Macro-to-microchannel transition in two-phase flow: Part 1 – Two-phase flow patterns and film thickness measurements

Interface-fitted moving mesh method for axisymmetric two-phase flow in microchannels

Flow Boiling in Horizontal Tubes. Part 3; Development of a New Heat Transfer Model Based on Flow Pattern

Time-strip visualization and thermo-hydrodynamics in a Closed Loop Pulsating Heat Pipe