Effect of Mixed Convective Heat Transfer on Interior Helium Temperature of High-Altitude-Cruising Airships

2013 ◽  
Vol 470 ◽  
pp. 516-520 ◽  
Author(s):  
Yong Qiang Yang ◽  
Yun Peng Ma ◽  
Zhe Wu
Keyword(s):  
Heat Transfer ◽  
Thermal Analysis ◽  
High Altitude ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Pressure Difference ◽  
Convective Heat Transfer Coefficient ◽  
Analysis Model ◽  
Forced Convective Heat Transfer ◽  
Air Speed

This paper aims to establish a thermal analysis model for stratospheric airships. Mixed convective heat transfer between envelope and air has been specially considered. Thermal analysis of HAB on the summer solstice was carried out in this paper, results show that forced convective heat transfer coefficient increases obviously as the air speed decreasing, which will enhance the heat transfer between envelope and atmospheric. The pressure difference decreases obviously as air speed increasing during the whole day. Therefore HAB(high altitude balloon) should increase the air speed to reduce the pressure difference, which will enhance the safety of HAB.

scholarly journals Influence of environmental boundary conditions on convective heat transfer coefficients of wall internal surface

2021 ◽  
Vol 312 ◽  
pp. 02012
Author(s):  
Tullio de Rubeis ◽  
Luca Evangelisti ◽  
Claudia Guattari ◽  
Roberto De Lieto Vollaro ◽  
Francesco Asdrubali ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Convective Heat Transfer Coefficient ◽  
Internal Surface ◽  
Heat Fluxes ◽  
Transfer Coefficients ◽  
Air Speed ◽  
Velocity Changes ◽  
Forced Air

In this study, convective heat transfer phenomena were investigated by means of a Guarded Hot Box (GHB) apparatus. An experimental setup characterized by air and surface temperature probes, and a hot-wire anemometer was used. Five small fans were installed in the metering chamber to generate a forced air flow characterized by different velocity values. So, the GHB was used for investigating the influence of different air speed values on internal convective coefficients. Considering horizontal heat fluxes, an internal convective coefficient values of 2.5 W/m2K is reported in the Standard ISO 6946. However, no exhaustive description about this value is provided. The aim of this work is to experimentally determine the internal thermal surface resistance, quantifying how the convective heat transfer coefficient varies as air velocity changes.

Heat Transfer Characteristics of an Array of Impinging Gaseous Slot Jets

2011 ◽  
Vol 396-398 ◽  
pp. 2234-2239
Author(s):  
Zu Ling Liu ◽  
Cheng Bo Wu ◽  
Xian Jun Wang ◽  
Zheng Rong Zhang
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Nozzle Exit ◽  
Convective Heat Transfer Coefficient ◽  
Heat Transfer Characteristics ◽  
Forced Convective Heat Transfer

A comprehensive experiment was conducted for heat transfer characteristics for an array of impinging gaseous slot jets to a flat plate with strong turbulence (nozzle exit Reynolds number Re=22500~64700).Find that turbulence intensity of flow has an important influence on local forced convective heat transfer coefficient. Meanwhile, the nozzle-to-plate spacing and nozzle exit Reynolds number Re would affect the mean forced convective heat transfer coefficient of the slot jets. And heat transfer efficiency of slot jets has been set to show the relation between ability of the jets and energy consumption of gas supply.

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