scholarly journals Heat transfer from glass melt to cold cap: Melting rate correlation equation

2018 ◽  
Vol 10 (2) ◽  
pp. 143-150 ◽  
Author(s):  
Pavel Hrma ◽  
Richard Pokorny ◽  
SeungMin Lee ◽  
Albert A. Kruger
Keyword(s):  
Heat Transfer ◽  
Correlation Equation ◽  
Melting Rate ◽  
Rate Correlation

scholarly journals Experimental analysis and ANN prediction on performances of finned oval-tube heat exchanger under different air inlet angles with limited experimental data

Open Physics ◽  
2020 ◽  
Vol 18 (1) ◽  
pp. 968-980
Author(s):  
Xueping Du ◽  
Zhijie Chen ◽  
Qi Meng ◽  
Yang Song
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Heat Exchanger ◽  
Correlation Equation ◽  
Tube Heat Exchanger ◽  
Flow Friction ◽  
Air Inlet ◽  
Comparison Results ◽  
Wide Range ◽  
Oval Tube

Abstract A high accuracy of experimental correlations on the heat transfer and flow friction is always expected to calculate the unknown cases according to the limited experimental data from a heat exchanger experiment. However, certain errors will occur during the data processing by the traditional methods to obtain the experimental correlations for the heat transfer and friction. A dimensionless experimental correlation equation including angles is proposed to make the correlation have a wide range of applicability. Then, the artificial neural networks (ANNs) are used to predict the heat transfer and flow friction performances of a finned oval-tube heat exchanger under four different air inlet angles with limited experimental data. The comparison results of ANN prediction with experimental correlations show that the errors from the ANN prediction are smaller than those from the classical correlations. The data of the four air inlet angles fitted separately have higher precisions than those fitted together. It is demonstrated that the ANN approach is more useful than experimental correlations to predict the heat transfer and flow resistance characteristics for unknown cases of heat exchangers. The results can provide theoretical support for the application of the ANN used in the finned oval-tube heat exchanger performance prediction.

scholarly journals Numerical Simulation of the Impact of the Heat Source Position on Melting of a Nano-Enhanced Phase Change Material

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1425
Author(s):  
Tarek Bouzennada ◽  
Farid Mechighel ◽  
Kaouther Ghachem ◽  
Lioua Kolsi
Keyword(s):  
Heat Transfer ◽  
Phase Change ◽  
Phase Change Material ◽  
Numerical Study ◽  
Melting Rate ◽  
Heat Transfer Fluid ◽  
Commercial Code ◽  
Tube Position ◽  
The Impact ◽  
Change Material

A 2D-symmetric numerical study of a new design of Nano-Enhanced Phase change material (NEPCM)-filled enclosure is presented in this paper. The enclosure is equipped with an inner tube allowing the circulation of the heat transfer fluid (HTF); n-Octadecane is chosen as phase change material (PCM). Comsol-Multiphysics commercial code was used to solve the governing equations. This study has been performed to examine the heat distribution and melting rate under the influence of the inner-tube position and the concentration of the nanoparticles dispersed in the PCM. The inner tube was located at three different vertical positions and the nanoparticle concentration was varied from 0 to 0.06. The results revealed that both heat transfer/melting rates are improved when the inner tube is located at the bottom region of the enclosure and by increasing the concentration of the nanoparticles. The addition of the nanoparticles enhances the heat transfer due to the considerable increase in conductivity. On the other hand, by placing the tube in the bottom area of the enclosure, the liquid PCM gets a wider space, allowing the intensification of the natural convection.

An Experimental Study of Free Corrective Heat Transfer in a Parallelogrammic Enclosure

1983 ◽  
Vol 105 (3) ◽  
pp. 433-439 ◽  
Author(s):  
N. Seki ◽  
S. Fukusako ◽  
A. Yamaguchi
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Nusselt Number ◽  
Correlation Equation ◽  
Transformer Oil ◽  
Experimental Measurements ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Prandtl Numbers ◽  
Rayleigh Numbers

Experimental measurements are presented for free convective heat transfer across a parallelogrammic enclosure with the various tilt angles of parallel upper and lower walls insulated. The experiments covered a range of Rayleigh numbers between 3.4 × 104 and 8.6 × 107, and Prandtl numbers between 0.70 and 480. Those also covered the tilt angles of the parallel insulated walls with respect to the horizontal, φ, of 0, ±25, ±45, ±60, and ±70 deg under an aspect ratio of H/W = 1.44. The fluids used were air, transformer oil, and water. It was found that the heat transfer coefficients for φ = −70 deg were decreased to be about 1/18 times those for φ = 0 deg. Experimental results are given as plots of the Nusselt number versus the Rayleigh number. A correlation equation is given for the Nusselt number, Nu, as a function of φ, Pr, and Ra.

Natural Convection in Horizontal Thin-Walled Honeycomb Panels

1973 ◽  
Vol 95 (4) ◽  
pp. 439-444 ◽  
Author(s):  
K. G. T. Hollands
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Fluid Layer ◽  
Convection Heat Transfer ◽  
Correlation Equation ◽  
Wave Number ◽  
Equivalent Wave ◽  
Side Walls ◽  
The Stability ◽  
Rayleigh Numbers

This paper presents an experimental study of the stability of and natural convection heat transfer through a horizontal fluid layer heated from below and constrained internally by a honeycomb. Examination of the types of boundary conditions exacted on the fluid at the cell side-walls has shown that there are three limiting cases: (1) perfectly conducting side-walls; (2) perfectly adiabatic side-walls; and (3) side-walls having zero thickness. Experiments described in this paper approach the latter category. The fluid used is air and the honeycomb used is square-celled. Measured critical Rayleigh numbers are found to be intermediate between those applying to cases (1) and (2), and consistent with an “equivalent wave number” of approximately 0.95 times that for case (1). The measured natural convective heat transfer after instability is found to be significantly less than that predicted by the Malkus-Veronis power integral technique. However, it is found to approach asymptotically the heat transfer which would take place through a similar fluid layer unconstrained by a honeycomb. A general correlation equation for the heat transfer is given.

Natural Heat Transfer Coefficients of Chicken Drum Shaped Bodies

2005 ◽  
Vol 1 (3) ◽  
Author(s):  
Michael Ngadi ◽  
Julian N. Ikediala
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Correlation Equation ◽  
Deep Fat Frying ◽  
Heat Transfer Correlation ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Increasing Temperature ◽  
The Heat Transfer Coefficient

Average heat transfer coefficients of chicken drum shaped bodies were estimated using aluminum chicken drum shaped models. Three model drum sizes namely small, medium and large, and three frying oil viscosities for three temperature differences were used. Estimated heat transfer coefficients were in the range from 67 to 163 W/m²K. Increasing temperature difference increased heat transfer coefficient. Conversely, increasing the size of the chicken drum model bodies and oil viscosities decreased the heat transfer coefficient. A heat transfer correlation equation between average Nu and Ra was derived. The methodology developed in this study could be used to estimate heat transfer coefficients of chicken drum during deep-fat frying.

Ice Formation and Heat Transfer With Water Flow Around Isothermally Cooled Cylinders Arranged in a Line

1990 ◽  
Vol 112 (3) ◽  
pp. 707-713 ◽  
Author(s):  
T. Hirata ◽  
H. Matsui
Keyword(s):  
Heat Transfer ◽  
Cold Water ◽  
Flow Direction ◽  
Storage System ◽  
Local Heat Transfer ◽  
Energy Storage System ◽  
Correlation Equation ◽  
Local Heat ◽  
Ice Formation ◽  
Transfer Coefficients

The ice formation phenomenon and heat transfer around isothermally cooled cylinders that are lined up in the direction of flow in a crossflow of cold water were examined experimentally. Under the conditions of low Reynolds numbers and low cooling temperatures, the cylinders became linked by an ice layer. The amount of ice formed around the cylinders was much more than that for a single cylinder. A correlation equation was proposed for the amount of linked ice around the cooled cylinders. It was found that the local heat transfer coefficients on the linked ice surface showed an alternating decrease and increase in the flow direction. The mean value of the local Nusselt number showed the same characteristic as that on a flat plate in a turbulent flow. A dimensionless parameter that represents how efficiently the cylinders can work as a thermal energy storage system was introduced.

Nucleate Boiling Performance of Refrigerants and Refrigerant-Oil Mixtures

1980 ◽  
Vol 102 (4) ◽  
pp. 701-705 ◽  
Author(s):  
S. Chongrungreong ◽  
H. J. Sauer
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Significant Influence ◽  
Correlation Equation ◽  
Nucleate Boiling ◽  
Experimental Results ◽  
General Correlation ◽  
Oil Mixtures ◽  
The Heat Transfer Coefficient

Current and previous studies by the authors and others have shown shown that the carryover of oil in refrigeration systems can have a significant influence on the boiling performance in the evaporator of refrigeration systems. This investigation was conducted primarily to develop a general correlation equation for predicting the heat transfer coefficient for refrigerants and refrigerant-oil mixtures under pool boiling conditions. Experimental results were obtained to establish the validity of the correlation equation.

An Investigation of the Liquid Distribution in Annular-Mist Flow

1970 ◽  
Vol 92 (4) ◽  
pp. 651-658 ◽  
Author(s):  
J. T. Pogson ◽  
J. H. Roberts ◽  
P. J. Waibler
Keyword(s):  
Heat Transfer ◽  
Film Thickness ◽  
Liquid Film ◽  
Flow Rate ◽  
Droplet Size Distribution ◽  
Correlation Equation ◽  
Vapor Flow ◽  
Two Phase ◽  
Liquid Distribution ◽  
Liquid Film Flow

The results of an experimental investigation of the average liquid film thickness are presented for vertical upward annular-mist two-phase flow, with and without heat transfer. The effects on the film thickness for variations in vapor flow rate, liquid flow rate, vapor density, and heat transfer are described. A correlation equation is presented for the local time-averaged thickness and for the droplet size distribution. In addition, an equation is given for the liquid film flow rate as a function of the average film thickness.

Free Convection Heat Transfer Characteristics in a Melt Water Layer

1980 ◽  
Vol 102 (3) ◽  
pp. 550-556 ◽  
Author(s):  
Yin-Chao Yen
Keyword(s):  
Heat Transfer ◽  
Temperature Profile ◽  
Constant Temperature ◽  
Water Layer ◽  
Melting Rate ◽  
Rate Measurement ◽  
Heat Transfer Characteristics ◽  
Layer Depth ◽  
Onset Of Convection ◽  
Transfer Characteristics

An experimental study was conducted on the formation of a water layer containing a maximum density, its effect on the onset of convection, and the heat transfer characteristics of such a system. This water layer was formed by one-dimensional melting (either from below or above) of a cylinder of bubble-free ice. For melting from above, with a melting rate measurement, the warm plate temperature Th varied from 4.16 to 13.09°C with initial ice temperatures T0 of −6.5 and −13°C, respectively. For experiments with a measurement of temperature profile, Th varied from 11.75 to 39.90°C with T0 at −12 and −15°C. For melting from below with a melting rate measurement, Th ranged from 7.70 to 25.50°C with four T0’s from −4.8 to −22°C. The layer depth at the onset of convection was determined by locating the inflection point on the water layer depth versus time curve, and was compared with layer depth calculated from a linear stability analysis of an identical problem. The results were compared with the analytical work of Veronis and were found to be in excellent agreement. Formation of a constant temperature layer was observed by measuring the water temperature distribution as melting progressed. The constant temperature was found to be dependent on Th for melting from below but was a constant for melting from above. The heat flux to the melting surface increased linearly with Th for melting from below, but had a weaker dependence for melting from above. Non-dimensional mean temperature profiles of the water layer were found to be in good agreement with those by Adrian for melting from above. In the case of melting from below, the mean temperature profile also fell into a single line with a somewhat higher value in the convection layer.

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