scholarly journals Numerical studies of heat transfer and gas migration processes in relation to in situ vitrification

1990 ◽  
Author(s):  
G.L. Hawkes ◽  
R.J. MacKinnon ◽  
P.E. Murray
Keyword(s):  
Heat Transfer ◽  
Gas Migration ◽  
Numerical Studies

Experimental and Numerical Study on the Effects of the Relative Position of Film Hole and Orientation Ribs on the Film Cooling With Ribbed Cross-Flow Coolant Channel

2020 ◽  
Author(s):  
Bingran Li ◽  
Cunliang Liu ◽  
Lin Ye ◽  
Huiren Zhu ◽  
Fan Zhang
Keyword(s):  
Heat Transfer ◽  
Relative Position ◽  
Film Cooling ◽  
Numerical Study ◽  
Cross Flow ◽  
Internal Cooling ◽  
Transfer Coefficients ◽  
Cooling Performance ◽  
Heat Transfer Coefficients ◽  
Numerical Studies

Abstract To investigate the application of ribbed cross-flow coolant channels with film hole effusion and the effects of the internal cooling configuration on film cooling, experimental and numerical studies are conducted on the effect of the relative position of the film holes and different orientation ribs on the film cooling performance. Three cases of the relative position of the film holes and different orientation ribs (post-rib, centered, and pre-rib) in two ribbed cross-flow channels (135° and 45° orientation ribs) are investigated. The film cooling performances are measured under three blowing ratios by the transient liquid crystal measurement technique. A RANS simulation with the realizable k-ε turbulence model and enhanced wall treatment is performed. The results show that the cooling effectiveness and the downstream heat transfer coefficient for the 135° rib are basically the same in the three position cases, and the differences between the local effectiveness average values for the three are no more than 0.04. The differences between the heat transfer coefficients are no more than 0.1. The “pre-rib” and “centered” cases are studied for the 45° rib, and the position of the structures has little effect on the film cooling performance. In the different position cases, the outlet velocity distribution of the film holes, the jet pattern and the discharge coefficient are consistent with the variation in the cross flow. The related research previously published by the authors showed that the inclination of the ribs with respect to the holes affects the film cooling performance. This study reveals that the relative positions of the ribs and holes have little effect on the film cooling performance. This paper expands and improves the study of the effect of the internal cooling configuration on film cooling and makes a significant contribution to the design and industrial application of the internal cooling channel of a turbine blade.

The Research of Energy Conversion and Heat Transfer in the Ceramic Foams of Solar Energy Converter

2011 ◽  
Author(s):  
Yangbo Deng ◽  
Fengmin Su ◽  
Chunji Yan
Keyword(s):  
Heat Transfer ◽  
Numerical Model ◽  
Solar Radiation ◽  
Solar Energy ◽  
Numerical Models ◽  
Air Flow ◽  
Energy Converter ◽  
Ceramic Foams ◽  
Numerical Studies ◽  
Flow Through

The solar energy converter in Concentrated Solar Power (CSP) system, applies the solid frame structure of the ceramic foams to receive the concentrated solar radiation, convert it into thermal energy, and heat the air flow through the ceramic foams by convection heat transfer. In this paper, first, the pressure drops in the studied ceramic foams were measured under all kinds of flow condition. Based on the experimental results, an empirical numerical model was built for the air flow through ceramic foams. Second, a 3-D numerical model was built, for the receiving and conversion of the solar energy in the ceramic foams of the solar energy converter. Third, applying two aforementioned numerical models, the numerical studies of the thermal performance were carried out, for the solar energy converter filled with the ceramic foams, and results show that the structure parameters of the ceramic foams, the effective reflective area and the solar radiation intensity of the solar concentrator, have direct impacts on the absorptivity and conversion efficiency of the solar energy in the solar energy converter. And the results of the numerical studies are found to be in reasonable agreement with the experimental measurements. This paper will provide a reference for the design and manufacture of the solar energy converter with the ceramic foams.

scholarly journals Heat Transfer Augmentation through Different Jet Impingement Techniques: A State-of-the-Art Review

Energies ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6458
Author(s):  
Liaqat Hussain ◽  
Muhammad Mahabat Khan ◽  
Manzar Masud ◽  
Fawad Ahmed ◽  
Zabdur Rehman ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Phase Change Materials ◽  
Jet Impingement ◽  
Target Surface ◽  
Industrial Applications ◽  
Heat Transfer Augmentation ◽  
Numerical Studies ◽  
Single Jet ◽  
Jet Nozzle ◽  
Future Work

Jet impingement is considered to be an effective technique to enhance the heat transfer rate, and it finds many applications in the scientific and industrial horizons. The objective of this paper is to summarize heat transfer enhancement through different jet impingement methods and provide a platform for identifying the scope for future work. This study reviews various experimental and numerical studies of jet impingement methods for thermal-hydraulic improvement of heat transfer surfaces. The jet impingement methods considered in the present work include shapes of the target surface, the jet/nozzle–target surface distance, extended jet holes, nanofluids, and the use of phase change materials (PCMs). The present work also includes both single-jet and multiple-jet impingement studies for different industrial applications.

scholarly journals Analysis of heat transfer coefficient of rammed earth wall in traditional houses in Vojvodina

2017 ◽  
Vol 21 (6 Part B) ◽  
pp. 2919-2930
Author(s):  
Vesna Lovec ◽  
Milica Jovanovic-Popovic ◽  
Branislav Zivkovic
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Thermal Characteristics ◽  
Rammed Earth ◽  
Single Family ◽  
Building Stock ◽  
Earth Structures ◽  
Rammed Earth Wall

Traditional Vojvodina house represents an important part of the building stock of the northern Serbian province of Vojvodina. The research examines the thermal transmittance of the walls of rammed earth, which is the basic structural and fa?ade element of traditional Vojvodina house, in two ways: by calculations in accordance with Serbian regulations and by measuring in situ. Parameters obtained from the measurements are compared with the calculated values for the three typical traditional Vojvodina rammed earth single family residential houses. The comparison between the values of the heat transfer coefficient, obtained by the calculation, and the results determined by in situ measurements show significant differences. It indicates that the thermal characteristics are better than calculated ones according to national regulations, but at the same time that, due to the complexity of the rammed earth walls and differences in the rammed earth structures, the results differ from case to case and can not be standardized.

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