Parametric Study Of Heat Transfer Research Articles

Parametric Study of Heat Transfer from An Annulus with Rotating Inner Cylinder

The present article presents a parametric study on the forced convection heat transfer from a heated rotating inner cylinder with the stationary outer cylinder in the presence of an axial flow. Both laminar and turbulent flows of air are considered. The following parameters were considered in the present research work: Reynolds number, the rotational speed of the inner cylinder, heat flux dissipated from the inner cylinder in addition to the annulus gap width. The results are presented to show the variation of the Nusselt number with the governing parameters for both laminar and fully turbulent flow. The results of the present study show that increasing either the Reynolds number, rotation speed, and/or the gap distance, leads to improve the cooling and enhancing the heat dissipation from the inner cylinder for both laminar and turbulent flows. The present numerical results show also that various heat flux values from the inner rotating cylinder have a negligible effect on the rate of the cooling process.

Parametric Study of Heat Transfer and Pressure Drop Characteristics of a Rectangular Offset Strip Fin Compact Heat Exchanger

Compact heat exchangers are of great topics of interest while we are dealing with the enhancement of heat transfer rate. In this study, a rectangular offset strip fin compact heat exchanger is taken into consideration. The purpose of this study is to develop a numerical model to study the heat transfer characteristics as well as the pressure drop characteristics. The parametric study was done in FLUENT with a three dimensional computational domain in which air is selected as working fluid. The analysis was confined to the flow in laminar region and so the Reynolds number was limited to 1000. The variation of friction factor and Colburn factor with Reynolds number is also analysed. The results obtained were analysed and were also compared with an existing correlation. The findings of this study may serve as a helping tool to develop a correlation for fluid flow in offset strip fin geometry.

Parametric study of heat transfer in an electric arc furnace and cooling system

The present study deals with a numerical investigation of an electric arc furnace (EAF). A model based on radiative heat transfer has been generated to estimate the temperature distribution inside the furnace. The obtained results from this model provide realistic and reasonable predictions of the temperature, comparing with the results of the experimental measurements of wall temperature. Based on calculated temperatures fields, full numerical analysis of the cooling panel was performed. The numerical results from the cooling system simulation were also compared with experimental measurements of outlet water temperature from experimental apparatus and showed good accuracy. In addition, a parametric study was carried out to determine the influence of geometrical parameters and slag layer formation inside the furnace on temperature distribution within the furnace. It was concluded that the diameter of the furnace is the main geometrical parameter affecting temperature distribution in a furnace and the roof inclination angle appeared to be of secondary importance. The effects of slag layer thickness on the walls were also numerically investigated and it was observed that the formation of slag layer on the furnace walls has a significant impact on the safe operation of the furnace and improved furnace efficiency.

Experimental Study of Heat Transfer Parameters of Impingement Heating System Represented by Conductive Target Plate of Resistive film

Experimental Study of Heat Transfer Parameters of Impingement Heating System Represented by Conductive Target Plate of Resistive film

A Parametric Study of Heat Transfer for the Optimization of Fin Sinks

Fin heat sinks are the most widely used type of heat sink for cooling purposes nowadays where space is a key factor, such as for the cooling of electronic equipment. Improved cooling capacity and the lowest possible thermal resistance in the design optimization process of these sink geometries means that we should consider a number of variable parameters, which can involve tedious design processes that are almost impossible to approximate to a sufficient degree of accuracy without computer simulation tools. The principal parameters are the heat dissipation base area, fin size, shape and material and the heat transfer coefficient. Computer numerical simulation tools greatly assist the design process, allowing in turn a greater range and more accurate analysis of the problem itself. In this study, we develop a design tool called "Opti-fin" for a Matlab ® environment that allows the user to configure a fin on the basis of the material and the thermal heat that will be released. Our study also includes a realistic estimation of fluid (air) flows that control the temperature dependency of the fin. This tool has been validated by computational fluid dynamic simulations using ANSYS-FLUENT®, in which the results of the simulation and the actual triangular shaped fin showed a remarkable similarity.

Extensive Parametric Study of Heat Transfer to Arrays of Oblique Impinging Jets With Phase Change

This work presents the single- and two-phase results of a parametric study investigating the performance of oblique jet arrays impinging at 45 deg on a 3.63 cm2 square copper heater surface using R-245fa. It was found that the parameters that most impact heat transfer changed as the system progressed from single- to two-phase flow behavior. The single-phase performance was governed by the jet geometry and the volumetric flow rate, while in the two-phase region, heat transfer performance was primarily affected by the fluid conditions and the heat flux applied. A single-phase correlation was developed to capture the low heat flux response, and the two-phase results were well-correlated by a pool boiling correlation. A new general correlation for jet impingement heat transfer with phase change is presented combining these correlations. Critical heat flux (CHF) data were compared with literature correlations and a new correlation was developed for arrays of boiling jets.

A parametric study of heat transfer in an air-cooled heat sink enhanced by actuated plates

Heat transfer in air-cooled heat sinks must be improved to meet thermal management requirements of modern microelectronics devices. This need is addressed by putting agitator plates into channels of a heat sink so that heat transfer is enhanced by agitation. A proof-of-concept exercise was computationally conducted in a single channel consisting of uniform-temperature base and two side walls and an adiabatic fourth wall. The channel side walls are fins of the heat sink fin array. The agitator plate is within the channel. Air flows through the channel and the agitator plate generates periodic motion in a transverse direction to the air flow and to the channel surface. Turbulence is generated along the tip of the agitator plate due to its periodical motion, resulting in substantial heat transfer enhancement in the channel. Heat transfer is enhanced by 61% by agitation for a representative situation. Translational operation of the plate induces 33% more heat transfer than a corresponding flapping operation. Heat transfer on the base surface increases sharply as the tip gap size between it and the agitator plate tip is decreased, while heat transfer on the sidewalls is insensitive to the tip gap size. Heat transfer from the channel wall to the flow increases linearly with increases of amplitude or frequency of the agitator plate. The primary operational parameter to the problem is the product of amplitude and frequency, with amplitude being slightly more influential than frequency.

Study of Heat Transfer Parameters in the Laminar Cooling Process for Hot-Rolled Strips

The laminar cooling process for the hot-rolled strip is very complex, and the identification of k related to the heat transfer is critical to improve the mathematic precision. So a study of heat transfer parameters is carried in the paper, and the proposed approach is based on the hybrid multi-intelligence technology, where the RBF neural networks, CBR have been used to obtain the parameter estimates. A number of tests using industrial data have been conducted where desired numerical results have been obtained.

TCPT-2006-096.R2: Micro Scale pin fin Heat Sinks —Parametric Performance Evaluation Study

A parametric study of heat transfer and pressure drop associated with forced flow of deionized water over five micro pin fin heat sinks of different spacing, arrangements, and shapes was conducted experimentally. Nusselt numbers and friction factors were obtained over Reynolds numbers ranging from 14 to 720. The thermal and hydraulic results were obtained to evaluate and compare the heat sinks performances at fixed mass flow rate, fixed pressure drop, and fixed pumping power. Two distinct regions of the Nusselt number dependency on the Reynolds number separated by a critical Reynolds number have been identified for unstreamlined pin fin devices while the streamlined device showed no slope change. The effects of spacing, shape of pin fins, and arrangement on friction factor and heat transfer were in agreement with existing literature. The results indicate that utilizing streamlined pin fin heat sinks can significantly enhance the thermal-hydraulic performance of the heat sink, but only at moderate Reynolds numbers.

A numerically-based parametric study of heat transfer off an inclined surface subject to impinging airflow

Impinging jets may be used to achieve enhanced local heat transfer for convective heating, cooling, or drying. The issuing jet may contact the surface normally or obliquely. Factors such as jet attachment, surface angle, jet angle and size, separation distance between jet orifice and surface of impingement, and trajectory influence heat transfer dramatically. This study addresses the thermal problem of jet impingement on an inclined surface and is motivated by the practical application of air jets issuing out of a defroster’s nozzles and impinging on the inclined windshield surface of a vehicle. The effects of incoming fluid velocity, openings’ geometry (circular vs. rectangular), number of openings, angle that the inclined surface makes with the horizontal plane and angle of impinging jet on heat transfer are examined. Fluid mechanics and heat transfer characteristics are exhibited in details for a configuration with three rectangular openings. A comparative study for other configurations is also featured. The results are correlated in terms of governing dimensionless parameters through numerically-based correlations that are useful for predicting heat transfer on an inclined surface subject to impinging airflow.

Parametric Study of Heat Transfer in Turbulent Gas−Solid Flow in Multiple Impinging Jets

Heat transfer in a dilute gas−particle suspension flow in multiple-slot impinging jets has been numerically investigated using a new Eulerian−Lagrangian method that accounts for conduction heat transfer due to particle−wall collisions. The numerical results are compared with available experimental data. Good agreement between experiment and simulation is obtained only if the additional conduction heat transfer due to particle−wall collisions is considered in the model. The effects of particle diameter, particle material properties and loading ratios, jet Reynolds number, impingement wall temperature, and direction of the gravitation vector on heat transfer are discussed.

Parametric Study of Heat Transfer in Injection Molding—Effect of Thermal Contact Resistance

Thermal contact resistance (TCR) plays an important role in the heat transfer during injection molding. However, there is no consensus on the magnitude of TCR to be used in simulation as most of the reported results are based on steady state experiments. A numerical simulation of the heat transfer in injection molding is used in studying its effect and significance. The TCR is shown to attain its maximum magnitude in the postfilling period, and more accurate values than those available in literature are required for a better simulation of the postfilling stage. The effect of interface gap formation between the plastic and the mold on the contact resistance is also studied. This shows that the gap may have contributed to the high magnitude of TCR reported from the one experimental study of TCR in injection molding. However, the gap formation is shown to be dependent on the part geometry as well as processing conditions—in terms of shrinkage and warpage effects. The gap is both a function of time and space (location on the part surface) and this makes any experimental determination of the gap and TCR difficult. [S1087-1357(00)01404-0]

Parametric study of heat transfer in two-dimensional fractured media

Parametric study of heat transfer in two-dimensional fractured media

Parametric study of heat transfer to an ice cylinder melting in air

A cylinder of ice was formed and suspended by a string from the end of a cantilevered beam. The beam had strain gages attached that were calibrated so that the weight of the ice cylinder was known during the time that it melted. Data on weight versus time were thus obtained and used to calculate values of Nusselt and Rayleigh Numbers over discrete intervals of time. The geometry of the ice cylinder precluded an exact determination of surface area and characteristic length for the time interval of interest. Consequently, three proposed expressions for characteristic length were tried and the one that yielded the highest correlation between Nusselt and Rayleigh numbers was selected as giving the best description. An equation was derived for each case.

Mathematical modeling and parametric study of heat transfer in Bridgman-Stockbarger growth of crystals

A one-dimensional heat transfer model was developed that allows calculation of interface melt temperature gradient and interface locations in Bridgman-Stockbarger growth. A set of parameters appear naturally in this analysis. A parametric study was used to predict the effect of these parameters on temperature gradient and interface location. The validity of the model was tested by comparison with experimental results on the MnBi/Bi eutectic system. The agreement is fair.