scholarly journals The Performance Prediction of The Mixed Convection In an Inclined Circular Tube Filled Porous Media Based on an Intelligent Control

2019 ◽  
Vol 26 (2) ◽  
pp. 9-14
Author(s):  
Musa Weis
Keyword(s):  
Heat Transfer ◽  
Porous Media ◽  
Mixed Convection ◽  
Relative Error ◽  
Circular Tube ◽  
Thermal Engineering ◽  
Number Range ◽  
Mean Relative Error ◽  
The Mean ◽  
And Storage

The porous media has a significant impact on the heat transfer and storage properties. The present study focuses on the heat transfer of the mixed convection through a circular tube that filled with a porous media at different angles using a neural network. An experiment had been performed for the Rayleigh number range from 108.54 to 907.73 and the Peclet number range 30.3.-510 using three tests for the heat flux. The result shows the mean relative error about 7.913% and the coloration coefficient (R2) Is 99.18% for the train data. The mean relative error about 6.641% and the R2 is 99.46%, for the test data. The results showed that effectiveness of ANN in the predicted thermal performance in thermal engineering applications such as heat transfer modeling using porous media with airflow.

scholarly journals Research experiment on infiltration and runoff in Jujube land of northern Shaanxi Province

2015 ◽  
Vol 368 ◽  
pp. 174-179
Author(s):  
X. Song ◽  
P. Bai
Keyword(s):  
Relative Error ◽  
Mean Squared Error ◽  
Shaanxi Province ◽  
Richards Equation ◽  
Mean Relative Error ◽  
The North ◽  
Cumulative Infiltration ◽  
Northern Shaanxi ◽  
The Mean ◽  
Research Experiment

Abstract. To provide guidance for the efficient use of rainwater in Jujube forests of the northern Shaanxi Province, research on the processes of infiltration and runoff under field simulated rainfall were conducted. The process of infiltration and runoff-yield on sloping land was simulated with Richards equation and the water balance equation under different rainfall intensities and soil water content, in the north of Shaanxi province. It reached results via comparing with observation results: the mean relative error of the period cumulative infiltration was less than 3%, with a root mean squared error (RSME) less than 0.3. The mean relative error of the period cumulative runoff was less than 12.5%, RSME < 0.4. The simulation results were reasonable; however, the simulation ponding time generally lagged behind measured ponding time probably because of spatial variation of saturated hydraulic conductivity and uneven rainfall.

BP Neural Network Based Animation Production Prediction

2014 ◽  
Vol 539 ◽  
pp. 475-478
Author(s):  
Ran Tao ◽  
Da Chao Yuan ◽  
Gang Yi Hu
Keyword(s):  
Neural Network ◽  
Relative Error ◽  
Bp Neural Network ◽  
Prediction Method ◽  
Coefficient Of Determination ◽  
Mean Relative Error ◽  
Training Samples ◽  
The Mean ◽  
Production Prediction

In order to research the basic condition of animation production, this article chooses BP Neural Network to predict the animation production. We select 13 test samples, selected nine of them randomly as training samples, and the remaining four as the test samples. The coefficient of determination is 0.99839 and the mean relative error is 0.186125. The result shows that BP Neural Network is an effective prediction method.

Turbulent convection in a horizontal layer of water

1973 ◽  
Vol 60 (1) ◽  
pp. 141-159 ◽  
Author(s):  
T. Y. Chu ◽  
R. J. Goldstein
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Rayleigh Number ◽  
Power Law ◽  
Bounding Surface ◽  
Interferometric Method ◽  
Number Range ◽  
Mean Temperature ◽  
The Mean ◽  
Rayleigh Numbers

Overall heat transfer and mean temperature distribution measurements have been made of turbulent thermal convection in horizontal water layers heated from below. The Nusselt number is found to be proportional to Ra0·278 in the range 2·76 × 105 < Ra < 1·05 × 108. Eight discrete heat flux transitions are found in this Rayleigh number range. An interferometric method is used to measure the mean temperature distribution for Rayleigh numbers between 3·11 × 105 and 1·86 × 107. Direct visual and photographic observations of the fluctuating interferogram patterns show that the main heat transfer mechanism is the release of thermals from the boundary layers. For relatively low Rayleigh numbers (up to 5 × 105) many of the thermals reach the opposite surface and coalesce to form large masses of relatively warm fluid near the cold surface and masses of cold fluid near the warm surface, resulting in a temperature-gradient reversal. With increasing Rayleigh numbers, fewer and fewer thermals reach the opposite bounding surface and the thermals show persistent horizontal movements near the bounding surfaces. The central region of the layer becomes an isothermal core. The mean temperature distributions for the high Rayleigh number range are found to follow a Z−2 power law over a considerable range, where Z is the distance from the bounding surface. A very limited agreement with the theoretically predicted Z−1 power law is also found.

Non-Darcy Mixed Convection With Thermal Dispersion in a Saturated Porous Medium

2009 ◽  
Vol 132 (1) ◽  
Author(s):  
V. V. Sobha ◽  
R. Y. Vasudeva ◽  
K. Ramakrishna ◽  
K. Hema Latha
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Porous Media ◽  
Nusselt Number ◽  
Mixed Convection ◽  
Vertical Plate ◽  
Saturated Porous Medium ◽  
Thermal Dispersion ◽  
Convection In Porous Media ◽  
Infinite Vertical Plate

Thermal dispersion due to local flows is significant in heat transfer with forced convection in porous media. The effects of parametrized melting (M), thermal dispersion (D), inertia (F), and mixed convection (Ra/Pe) on the velocity distribution, temperature, and Nusselt number on non-Darcy, mixed convective heat transfer from an infinite vertical plate embedded in a saturated porous medium are examined. It is observed that the Nusselt number decreases with increase in melting parameter and increases with increase in thermal dispersion.

Mixed-Convection Laminar Film Condensation on an Inclined Elliptical Tube

2000 ◽  
Vol 123 (2) ◽  
pp. 294-300 ◽  
Author(s):  
M. Mosaad
Keyword(s):  
Heat Transfer ◽  
Mixed Convection ◽  
Circular Tube ◽  
Film Condensation ◽  
Equivalent Diameter ◽  
Laminar Film ◽  
Laminar Film Condensation ◽  
Wide Range ◽  
Convection Dominated ◽  
The Heat Transfer Coefficient

The present theoretical study concerns with mixed-convection laminar film condensation outside an inclined elliptical tube with isothermal surface. The assumptions used are as in the classical Nusselt-Rohsenow theory, however, with considering the interfacial vapor shear by extending a circular-tube shear model developed in a previous study. An equivalent diameter, based on equal surface area, is introduced in the analysis to enable comparison with circular tubes. For zero ellipticity, the approach simplifies to the circular tube model developed in our previous work. A numerical solution has been obtained for a wide range of the independent parameters. The results indicate that the heat transfer performance of the inclined elliptical tube enhances with the increase of tube ellipticity compared to an inclined circular tube of equivalent diameter. For forced-convection-dominated film condensation, the rate of this enhancement in the heat transfer coefficient is found smaller than that for pure-free-convection film.

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