Molecular-to-Large-Scale Heat Transfer With Multiphase Interfaces: Current Status and New Directions

2009 ◽  
Vol 131 (12) ◽  
Author(s):  
Raj M. Manglik ◽  
Milind A. Jog
Keyword(s):  
Heat Transfer ◽  
Large Scale ◽  
Film Coating ◽  
Spray Cooling ◽  
Current Status ◽  
Experimental Investigations ◽  
Interfacial Behavior ◽  
Two Phase ◽  
New Directions ◽  
Momentum And Heat Transfer

The scientific understanding of multiphase interfaces and the associated convective mass, momentum, and heat transport across and along their boundaries, provide the fundamental underpinnings of the advancement of boiling heat transfer, two-phase flows, heat pipes, spray cooling, and droplet-film coating, among many other engineering applications. Numerous studies have tried to characterize the interfacial behavior and model their mechanistic influences either directly or implicitly via parametric experimental investigations and/or simulations. The goal of advancing our understanding as well as developing generalized, perhaps “universal,” and more accurate phenomenological or mechanistic correlations, for predicting mass, momentum, and heat transfer, continues to engage the worldwide research community. A collection of some such current investigations that are representative of both basic and applied issues in the field is presented in this special issue of the Journal of Heat Transfer.

Experimental investigations of momentum and heat transfer in pulse detonation engines

2002 ◽  
Vol 29 (2) ◽  
pp. 2847-2854 ◽  
Author(s):  
Jiro Kasahara ◽  
Kouki Takazawa ◽  
Takakage Arai ◽  
Yu Tanahashi ◽  
Shingo Chiba ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Experimental Investigations ◽  
Pulse Detonation Engines ◽  
Pulse Detonation ◽  
Momentum And Heat Transfer

Experimental Study of Condensation Flow Inside Horizontal Smooth, Herringbone and Three Enhanced Surface Tubes

2017 ◽  
Author(s):  
Xiaolong Yan ◽  
Wei Li ◽  
Weiyu Tang ◽  
Hua Zhu ◽  
Zhijian Sun ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Mass Flux ◽  
Saturation Temperature ◽  
Horizontal Tube ◽  
Working Fluid ◽  
Experimental Investigations ◽  
Enhancement Effect ◽  
Two Phase ◽  
Inner Diameter ◽  
Enhanced Surface

Enhanced condensation heat transfer of two-phase flow on the horizontal tube side receives more and more concerns for its fundamentality and importance. Experimental investigations on convective condensation were performed respectively in different horizontal tubes: (i) a smooth tube (11.43 mm, inner diameter); (ii) a herringbone tube (11.43 mm, fin root diameter); and (iii) three enhanced surface (EHT) tubes (11.5 mm, equivalent inner diameter): 1EHT tube, 2EHT-1 tube and 2EHT-2 tubes. The surface of EHT tubes is enhanced by arrays of dimples with the background of petal arrays. Experiments were conducted at a saturation temperature of approximately 320 K; 0.8 inlet quality; and 0.2 outlet quality; 72–181 kg·m−2·s−1 mass flux using R22, R32 and R410A as the working fluid. The refrigerant R32 presents great heat transfer performance than R410A and R22 at low mass flux due to its higher latent heat of vaporization and larger thermal conductivity. The heat enhancement ratio of the herringbone tube is 2.72–2.82, rated number one. The primary dimples on the EHT tube increase turbulence and flow separation, and the secondary petal pattern produce boundary layer disruption to many smaller scale eddies. The 2EHT tubes are inferior to the 1EHT tube. A performance factor is used to evaluate the enhancement effect except of the contribution of area increase.

An Extra Mode of Enhanced Heat Transfer by Oscillating Bubbles in Minichannels and Microchannels

2003 ◽  
Author(s):  
J. J. Schro¨der ◽  
S. Alraun
Keyword(s):  
Heat Transfer ◽  
High Speed ◽  
Bulk Water ◽  
Electrical Heating ◽  
Similar Process ◽  
Experimental Investigations ◽  
Physical Parameters ◽  
Two Phase ◽  
Model Calculations ◽  
Zero Crossing

Experimental investigations on heat transfer in tubular micro- or minichannel arrangements more often report on two-phase flow instabilities, pulsations or oscillations, which result in a remarkable influence on heat transfer efficiency. In order to explain the piston-like oscillations of the steam-plugs and water-slugs (-columns), the authors studied the somehow similar process which occurs in the worldwide known toy steam boat. Experiments have been performed which used a demonstration plant made of glass. By controlled electrical heating, high-speed video, pressure and local temperature measurements, the paths of energy have been disclosed. The results are as surprising as the effect of making gold from sand with respect to an equivalent axial heat-conductivity of the water-filled glass tube. Initiated by these results, an abstracting model is presented that analytically quantifies this new regenerating (oscillating and conducting) heat transfer mode e.g. concerning the combination of a heat recharging tube wall and an oscillating water column in a field of diminishing temperatures between the temperature of the boiler surface and the subcooled bulk water. By introducing these heat transfer details, the steam boat can give an answer, not only on frequency and amplitude of the oscillations, but on the steady state conditions for — or time-dependency of — the location of zero-crossing as well. Experimental results and model calculations are in good agreement and need no fitting factors. This is the base to discuss that process along with its physical parameters and compare it to the above mentioned observations in flow-boilers or pulsating heat pipes etc. which use microchannels or minichannels.

scholarly journals Experimental Investigation on Heat Transfer Mechanism of Air-Blast-Spray-Cooling System with a Two-Phase Ejector Loop for Aeronautical Application

Energies ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3963 ◽  
Author(s):  
Jia-Xin Li ◽  
Yun-Ze Li ◽  
Ben-Yuan Cai ◽  
En-Hui Li
Keyword(s):  
Heat Transfer ◽  
Droplet Size ◽  
Cooling System ◽  
Volumetric Flow Rate ◽  
Least Square Method ◽  
Spray Cooling ◽  
Cooling Capacity ◽  
Least Square ◽  
Two Phase ◽  
Air Blast

This paper presents an air-oriented spray cooling system (SCS) integrated with a two-phase ejector for the thermal management system. Considering its aeronautical application, the spray nozzle in the SCS is an air-blast one. Heat transfer performance (HTP) of air-water spray cooling was studied experimentally on the basis of the ground-based test. Factors including pressure difference between water-inlet-pressure (WIP) and spray cavity one (PDWIC) and the spray volumetric flow rate (SVFR) were investigated and discussed. Under a constant operating condition, the cooling capacity can be promoted by the growth factors of the PDWIC and SVFR with the values from 51.90 kPa to 235.35 kPa and 3.91 L ⋅ h − 1 to 14.53 L ⋅ h − 1 , respectively. Under the same heating power, HTP is proportional to the two dimensionless parameters Reynolds number and Weber number due to the growth of droplet-impacting velocity and droplet size as the increasing of PDWIC or SVFR. Additionally, compared with the factor of the droplet size, the HTP is more sensitive to the variation in the droplet-impacting velocity. Based on the experimental data, an empirical experimental correlation for the prediction of the dimensionless parameter Nusselt number in the non-boiling region with the relative error of only ± 10 % was obtained based on the least square method.

Momentum and Heat Transfer in Laminar Flow of Gas With Liquid-Droplet Suspension Over a Circular Cylinder

1967 ◽  
Vol 89 (2) ◽  
pp. 185-193 ◽  
Author(s):  
M. E. Goldstein ◽  
Wen-Jei Yang ◽  
J. A. Clark
Keyword(s):  
Heat Transfer ◽  
Circular Cylinder ◽  
Skin Friction ◽  
Gas Flow ◽  
Flow Problem ◽  
Liquid Droplet ◽  
Two Phase ◽  
Momentum And Heat Transfer ◽  
Layer Flow ◽  
Gas Liquid Flow

An analysis has been made to determine the heat transfer and friction characteristics in a two-phase (gas-liquid) flow over a circular cylinder. It is demonstrated that the resulting two-layer flow problem can be formulated exactly within the framework of laminar boundary layer theory. Two cases are studied; (1) For the parameter E greater or equal to 0.1 and the drop trajectories straight and, (2) For E less or equal to 0.1 and for any drop trajectory. Solutions obtained in power series include the local liquid-film thickness, velocity and temperature profiles, skin friction and Nusselt number. Numerical results disclose a significant increase in both heat transfer rate and skin friction over those of a pure gas flow. The theoretical prediction compares favorably with experimental results of Acrivos, et al. [1].

scholarly journals Impinging jets – a short review on strategies for heat transfer enhancement

2018 ◽  
Vol 32 ◽  
pp. 01013
Author(s):  
Ilinca Nastase ◽  
Florin Bode
Keyword(s):  
Heat Transfer ◽  
Large Scale ◽  
Short Review ◽  
Great Difficulty ◽  
Impinging Jets ◽  
Industrial Applications ◽  
Experimental Investigations ◽  
Small Scale ◽  
Strong Shear ◽  
Flow Phenomena

In industrial applications, heat and mass transfer can be considerably increased using impinging jets. A large number of flow phenomena will be generated by the impinging flow, such as: large scale structures, large curvature involving strong shear and normal stresses, stagnation in the wall boundary layers, heat transfer with the impinged wall, small scale turbulent mixing. All these phenomena are highly unsteady and even if nowadays a substantial number of studies in the literature are dedicated, the impinging jets are still not fully understood due to the highly unsteady nature and more over due to great difficulty of performing detailed numerical and experimental investigations.

scholarly journals Momentum and Heat Transfer in Two-Phase Bubble Flow in Concentric Annuli

1982 ◽  
Vol 25 (209) ◽  
pp. 1746-1754 ◽  
Author(s):  
Shinichi SARUWATARI ◽  
Yoshifusa SATO ◽  
Michio SADATOMI
Keyword(s):  
Heat Transfer ◽  
Bubble Flow ◽  
Two Phase ◽  
Momentum And Heat Transfer

scholarly journals Effect of spray cooling on heat transfer in a two-phase helium flow

Cryogenics ◽  
2013 ◽  
Vol 57 ◽  
pp. 74-87 ◽  
Author(s):  
S. Perraud ◽  
L. Puech ◽  
P. Thibault ◽  
B. Rousset ◽  
P.E. Wolf
Keyword(s):  
Heat Transfer ◽  
Spray Cooling ◽  
Helium Flow ◽  
Two Phase

Spray Cooling Heat Transfer Enhancement and Degradation Using Fractal-Like Micro-Structured Surfaces

2011 ◽  
Author(s):  
Alex Tulchinsky ◽  
Deborah V. Pence ◽  
James A. Liburdy
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Critical Heat Flux ◽  
Smooth Surface ◽  
Single Phase ◽  
High Volume ◽  
Spray Cooling ◽  
Volume Flux ◽  
Two Phase ◽  
Structured Surfaces

In the present study, spray cooling curves are presented for two micro-structured surfaces and are compared to smooth surface results. The micro-structured surfaces consisted of bio-inspired fractal-like geometries, denoted as grooves or fins, extending in a radial direction from the center to the periphery of a 37.8 mm circular disc. Depending on the location on the surface, dimensions of groove widths and heights varied from 100 to 500 μm, and 30 to 60 μm, respectively. Fin width and height dimensions remained constant over the surface at 127 and 60 μm, respectively. Results are presented as heat flux versus the surface-to-exit spray temperature difference at each of five volume flux conditions ranging from 0.54 to 2.04 × 10−3 m3/m2-s. Convection heat transfer coefficients are also presented for each case as a function of heat flux. Results indicate that at low and high volume fluxes, an improvement in heat transfer occurs in the single phase regime for the fin geometry. Enhancement in the single phase regime does not occur at the intermediate volume flux condition. In the two phase regime for the fin structure significant enhancements, up to 50%, are observed. Whereas the groove structure performs similarly to the smooth surface in the single phase regime and exhibits large degradation in the two phase and critical heat flux regimes, up to 50%. Critical heat flux for the fin surface compares well to that of the flat surface, with a slightly increase at high volume flux conditions.

Sign in / Sign up

Export Citation Format

Share Document