Inverse Arithmetic of the Equivalent Heat Transfer Coefficient of Mine Goaf

2011 ◽  
Vol 328-330 ◽  
pp. 1013-1016
Author(s):  
Shuai Heng ◽  
Feng Gao ◽  
Xing Guang Liu
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
High Temperature ◽  
Transfer Coefficient ◽  
Measured Data ◽  
Heat Sources ◽  
Calculating Method ◽  
Temperature Forecast ◽  
Working Face ◽  
Conservation Of Momentum

In order to calculate the dissipating capacity of heat sources and improve the veracity of airflow temperature forecast of mine, the equivalent heat transfer coefficient of mine goaf was calculated by means of inverse arithmetic based on the law of conservation of momentum and measured data from a high temperature working face. The results of calculation show that the equivalent heat transfer coefficient of mine goaf can reflect the heat dissipating characteristics generally and reduce the calculating method of the heat dissipating capacity of mine goaf, then it can be used better in the airflow temperature forecast.

scholarly journals Evaluation of Alternative Designs for a High Temperature Particle-to-sCO2 Heat Exchanger

2019 ◽  
Vol 141 (2) ◽  
Author(s):  
Clifford K. Ho ◽  
Matthew Carlson ◽  
Kevin J. Albrecht ◽  
Zhiwen Ma ◽  
Sheldon Jeter ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
High Temperature ◽  
Heat Exchanger ◽  
Transfer Coefficient ◽  
Fluidized Bed ◽  
Structural Reliability ◽  
Packed Bed ◽  
Heat Losses ◽  
Transient Operation

This paper presents an evaluation of alternative particle heat-exchanger designs, including moving packed-bed and fluidized-bed designs, for high-temperature heating of a solar-driven supercritical CO2 (sCO2) Brayton power cycle. The design requirements for high pressure (≥20 MPa) and high temperature (≥700 °C) operation associated with sCO2 posed several challenges requiring high-strength materials for piping and/or diffusion bonding for plates. Designs from several vendors for a 100 kW-thermal particle-to-sCO2 heat exchanger were evaluated as part of this project. Cost, heat-transfer coefficient, structural reliability, manufacturability, parasitics and heat losses, scalability, compatibility, erosion and corrosion, transient operation, and inspection ease were considered in the evaluation. An analytic hierarchy process was used to weight and compare the criteria for the different design options. The fluidized-bed design fared the best on heat transfer coefficient, structural reliability, scalability, and inspection ease, while the moving packed-bed designs fared the best on cost, parasitics and heat losses, manufacturability, compatibility, erosion and corrosion, and transient operation. A 100 kWt shell-and-plate design was ultimately selected for construction and integration with Sandia's falling particle receiver system.

Confined Liquid Jet Impingement on a Plate With Discrete Heating Elements

2005 ◽  
Author(s):  
Muhammad M. Rahman ◽  
Santosh K. Mukka
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Jet Impingement ◽  
Liquid Jet ◽  
Heat Sources ◽  
Average Heat Transfer Coefficient ◽  
Average Heat ◽  
Discrete Heat Sources ◽  
Solid Region

The primary focus of this paper is the conjugate heat transfer during vertical impingement of a two-dimensional (slot) submerged confined liquid jet using liquid ammonia as the working fluid. Numerical model for the heat transfer process has been developed. The solid region has been modeled along with the fluid region as a conjugate problem. Discrete heat sources have been used to study the overall effect on convective heat transfer. Simulation of discrete heat sources was done by introducing localized heat fluxes at various locations and their magnitudes being varied. Simulations are performed for two different substrate materials namely silicon and stainless steel. The equations solved in the liquid region included the conservation of mass, conservation of momentum, and conservation of energy. In the solid region, only the energy equation, which reduced to the heat conduction equation, had to be solved. The solid-fluid interface temperature showed a strong dependence on several geometric, fluid flow, and heat transfer parameters. The Nusselt number increased with Reynolds number. For a given flow rate, a higher heat transfer coefficient was obtained with smaller slot width and lower impingement height. For a constant Reynolds number, jet impingement height and plate thickness, a wider opening of the slot provided higher average heat transfer coefficient and higher average Nusselt number. A higher average heat transfer coefficient was seen at a smaller thickness, whereas a thicker plate provided a more uniform distribution of heat transfer coefficient. Higher thermal conductivity substrates also provided a more uniform heat distribution.

Experiment Study of Heat Transfer in Aeroengine Bearing Chambers

2011 ◽  
Vol 86 ◽  
pp. 448-453
Author(s):  
Xi Chuan Yuan ◽  
Hui Guo ◽  
Liang Yun Wang
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
High Temperature ◽  
Transfer Coefficient ◽  
Transfer Test ◽  
Air Flow ◽  
Experiment Study ◽  
Work Condition ◽  
Oil Flow ◽  
Turboshaft Engine

In this paper, a method of heat transfer test research in aeroengine bearing chamber has been introduced. The method attains the law of heat transfer in bearing chamber and the influence of heat transfer coefficient on bearing dn value, oil flow, supply oil temperature, sealing air flow by simulating the oil work condition in turboshaft engine typical high temperature bearing chamber.

scholarly journals Development of a Design Model for Airfoil Leading Edge Film Cooling

1985 ◽  
Author(s):  
A. R. Wadia ◽  
D. A. Nealy
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
High Temperature ◽  
Transfer Coefficient ◽  
Film Cooling ◽  
Leading Edge ◽  
Design Model ◽  
Coolant Temperature ◽  
Simultaneous Increase ◽  
Film Cooling Effectiveness

Leading edge showerhead cooling designs represent an important feature of certain classes of high temperature turbine airfoils. This paper outlines a methodology for predicting the surface temperatures of showerhead designs with spanwise injection through an array of discrete holes. The paper describes a series of experiments and analyses on scaled cylinder models with injection through holes inclined at 20, 30, 45, and 90 degrees for typical radial and circumferential spacing-to-diameter ratios of 10 and 4, respectively. The experiments were conducted in a wind tunnel on several stainless steel test specimens in which flow and heat transfer parameters were measured over the simulated airfoil leading edge surfaces. Based on the experiments, an engineering design model is proposed that treats the gas-to-surface heat transfer coefficient with film cooling in a manner suggested by a recent Purdue-NASA investigation and includes the important contribution of upstream (coolant inlet face) heat transfer. The experiments suggest that the averaged film cooling effectiveness in the showerhead region is primarily influenced by the inclination of the injection holes. The effectiveness parameter is not strongly affected by variations in coolant-to-gas stream pressure ratio, freestream Mach number, gas-to-coolant temperature ratio and gas stream Reynolds number. This is appropriately reflected in the design model in which the increase in coolant side heat transfer coefficient (with blowing ratio) is essentially offset by a simultaneous increase in the gas side film coefficient. The model is also employed to determine (inferentially) the average Stanton number reduction parameter for a series of pressure ratios varying from 1.004 to 1.3, Mach numbers ranging from 0.1 to 0.2, temperature ratios between 1.6 and 2.0, and Reynolds numbers ranging from 3.5 × 104 to 9.0 × 104. Design capabilities of the analytical model are explored for typical high temperature first stage turbine vanes and rotor blades operating at rotor inlet temperatures in excess of 1644°K.

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