Review of Artificial Bubble Generation Techniques and Their Suitability for Phenomenological Boiling Studies

2020 ◽  
Author(s):  
Navdeep Singh Dhillon
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Experimental Studies ◽  
Solid Surfaces ◽  
Interfacial Phenomena ◽  
Heat Transfer Fluid ◽  
Bubble Generation ◽  
Multiple Bubbles

Abstract The heterogeneous boiling of liquids on hot surfaces, despite its importance, is an extremely complicated and murky phenomenon. It involves the random probabilistic nucleation of multiple bubbles whose growth, interaction, and departure, further, depends on processes involving heat transfer, fluid flow, and interfacial phenomena. This, and the random tumultuous nature of boiling makes experimental studies of the process extremely difficult. For achieving a phenomenological understanding of boiling, several researchers have relied on experiments involving artificially generated bubbles on solid surfaces. In this paper, we evaluate these methods of artificial bubble generation and explore how closely they replicate actual heterogeneous boiling conditions experienced by bubbles. Based on this, we assess the suitability of these methods for conducting phenomenological boiling studies, and identify their potential advantages and drawbacks.

Experimental studies on micro-channel heat sink with different heat transfer fluid

2021 ◽  
Author(s):  
M. P. Dhanishk ◽  
P. Selvakumar ◽  
V. Ashwin ◽  
P. N. ArunKumar
Keyword(s):  
Heat Transfer ◽  
Heat Sink ◽  
Experimental Studies ◽  
Heat Transfer Fluid ◽  
Micro Channel

Call for Nominations – The Nusselt–Reynolds Prize Sponsored by Assembly of World Conferences on Experimental Heat Transfer, Fluid Mechanics, and Thermodynamics

2000 ◽  
Vol 402 ◽  
pp. 382-382
Author(s):  
Nobuhide Kasagi
Keyword(s):  
Heat Transfer ◽  
Fluid Mechanics ◽  
Design Theory ◽  
Experimental Studies ◽  
Heat Transfer Fluid ◽  
World Conference ◽  
Experimental Heat ◽  
Technological Advances ◽  
Visualization Techniques ◽  
Physical Phenomena

The Nusselt–Reynolds Prize has been established by the Assembly of World Conferences to commemorate outstanding contributions by Wilhelm Nusselt and Osborne Reynolds as experimentalists, researchers, educators, and authors. As many as three prizes may be bestowed at every World Conference, one in each of the areas of heat transfer, fluid mechanics, thermodynamics, or any combination of these.The prize will be bestowed for outstanding scientific and engineering contributions and eminent achievements in the fields of heat transfer, fluid mechanics, and thermodynamics through (1) experimental studies and analytical/numerical extension of the measurements, (2) development of experimental techniques, visualization techniques, and/or instrumentation, and/or (3) development of design theory (that needs experimental data) and theory-based experimental correlations. These contributions should yield a deeper insight into physical phenomena involved or should yield significant technological advances. In addition to research, the awardee(s) should have made outstanding contributions to the field through teaching, design, or a combination of such activities. The prize is based on achievement through publications or through the application of the science or art. Nationality, age, sex, and society membership will not be considered when evaluating qualifications of candidates. A candidate must be living at the time of designation as a recipient of the prize.The prize consists of a bronze plaque, and engrossed certificate, and an honorarium. The prize is administered by the Prize Board. The deadline for accepting nominations for the Prize is February 2, 2000. The prize will be awarded at the Fifth World Conference during September 24–28, 2001 in Thessaloniki, Greece where the prize winners will also present plenary lectures on their subjects.Nominators can obtain further information and download the nomination form from a webpage at http://www.thtlab.t.u-tokyo.ac.jp/N-Rprize.html/.

Combined Effects of Temperature and Velocity Jump on the Heat Transfer, Fluid Flow, and Entropy Generation Over a Single Rotating Disk

2010 ◽  
Vol 132 (11) ◽  
Author(s):  
A. Arikoglu ◽  
G. Komurgoz ◽  
I. Ozkol ◽  
A. Y. Gunes
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Entropy Generation ◽  
Rotating Disk ◽  
Heat Transfer Fluid ◽  
Combined Effects ◽  
Jump Conditions ◽  
Governing Equations ◽  
Velocity Jump ◽  
Effects Of Temperature

The present work examines the effects of temperature and velocity jump conditions on heat transfer, fluid flow, and entropy generation. As the physical model, the axially symmetrical steady flow of a Newtonian ambient fluid over a single rotating disk is chosen. The related nonlinear governing equations for flow and thermal fields are reduced to ordinary differential equations by applying so-called classical approach, which was first introduced by von Karman. Instead of a numerical method, a recently developed popular semi numerical-analytical technique; differential transform method is employed to solve the reduced governing equations under the assumptions of velocity and thermal jump conditions on the disk surface. The combined effects of the velocity slip and temperature jump on the thermal and flow fields are investigated in great detail for different values of the nondimensional field parameters. In order to evaluate the efficiency of such rotating fluidic system, the entropy generation equation is derived and nondimensionalized. Additionally, special attention has been given to entropy generation, its characteristic and dependency on various parameters, i.e., group parameter, Kn and Re numbers, etc. It is observed that thermal and velocity jump strongly reduce the magnitude of entropy generation throughout the flow domain. As a result, the efficiency of the related physical system increases. A noticeable objective of this study is to give an open form solution of nonlinear field equations. The reduced recurative form of the governing equations presented gives the reader an opportunity to see the solution in open series form.

Numerical Investigation of Heat Transfer, Fluid Flow and Formation of Emissions in Diesel Engines

2013 ◽  
Author(s):  
Müjdat Firat
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Combustion Engine ◽  
Operating Conditions ◽  
Heat Transfer Fluid ◽  
Nox Emissions ◽  
Combustion Pressure ◽  
Crank Angle ◽  
The Relationship ◽  
Hole Number

The present study has been performed on heat transfer, fluid flow and formation of emissions in a diesel engine by different engine parameters. The analysis aims at an investigation of flow field, heat transfer, combustion pressure and formation of emission by means of numerical simulation which is using as parameter; hole number of injector and crank angle. Numerical simulations are performed using the AVL-FIRE commercial software depending on the crank angle. This software is successfully used in internal combustion engine applications, and its validity has been accepted. In this paper, k-zeta-f is preferred as turbulence model and SIMPLE/PISO used as algorithms. Thus, results are presented with pressure traces, temperature curves and NOx and soot levels for engine operating conditions. In addition, the relationship between the spray behaviors and combustion characteristics including NOx emissions, soot emissions, combustion pressure and temperature were illustrated through this analysis.

scholarly journals Ground-Coupled Natural Circulating Devices (Thermosiphons): A Review of Modeling, Experimental and Development Studies

Inventions ◽  
2019 ◽  
Vol 4 (1) ◽  
pp. 14
Author(s):  
Messaoud Badache ◽  
Zine Aidoun ◽  
Parham Eslami-Nejad ◽  
Daniela Blessent
Keyword(s):  
Heat Transfer ◽  
Heat Exchangers ◽  
Low Temperatures ◽  
Experimental Studies ◽  
Heat Transfer Fluid ◽  
Fluid Circulation ◽  
Ground Heat Exchangers ◽  
Additional Equipment ◽  
Different Types ◽  
Overall Efficiency

Compared to conventional ground heat exchangers that require a separate pump or othermechanical devices to circulate the heat transfer fluid, ground coupled thermosiphons or naturallycirculating ground heat exchangers do not require additional equipment for fluid circulation in theloop. This might lead to a better overall efficiency and much simpler operation. This paper providesa review of the current published literature on the different types of existing ground coupledthermosiphons for use in applications requiring moderate and low temperatures. Effort has beenfocused on their classification according to type, configurations, major designs, and chronologicalyear of apparition. Important technological findings and characteristics are provided in summarytables. Advances are identified in terms of the latest device developments and innovative conceptsof thermosiphon technology used for the heat transfer to and from the soil. Applications arepresented in a novel, well-defined classification in which major ground coupled thermosiphonapplications are categorized in terms of medium and low temperature technologies. Finally,performance evaluation is meticulously discussed in terms of modeling, simulations, parametric,and experimental studies.

Thermodynamic Analysis of Heat and Fluid Flow in a Microchannel With Internal Fins

2009 ◽  
Author(s):  
Ramesh Narayanaswamy ◽  
Tilak T. Chandratilleke ◽  
Andrew J. L. Foong
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Thermodynamic Analysis ◽  
Entropy Generation ◽  
High Performance ◽  
Numerical Study ◽  
Three Dimensional ◽  
Heat Sinks ◽  
Heat Transfer Fluid ◽  
Internal Fins

Efficient cooling techniques are one of the critical design requirements for maintaining reliable operational characteristics of modern, miniaturised high performance electronic components. Microchannel heat sinks form an integral part of most devices used for thermal management in electronic equipment cooling. A microchannel of square cross section, having internal longitudinal fins is considered for analysis. A numerical study is carried out to investigate the fluid flow and heat transfer characteristics. Three-dimensional numerical simulations are performed on the microchannel in the presence of a hydrodynamically developed, thermally developing laminar flow. Further on, a thermodynamic analysis is carried out, for a range of fin heights and thermophysical parameters, in order to obtain the irreversibilities due to heat transfer and fluid flow within the microchannel. An optimum fin height, corresponding to the thermodynamically optimum conditions that minimize the entropy generation rates has been obtained. The effect of the presence of internal fins on the entropy generated due to heat transfer, fluid friction, and the total entropy generation is also provided.

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