Experimental Investigation of Heat Flux Characteristics on the Thermally Induced Vibration of a Slender Thin-Walled Beam

2020 ◽  
Vol 12 (05) ◽  
pp. 2050053
Author(s):  
Chao Fan ◽  
Yanqiang Bi ◽  
Jing Wang ◽  
Guoqing Liu ◽  
Zhihai Xiang
Keyword(s):  
Heat Flux ◽  
Thermal Characteristic ◽  
Transient Characteristics ◽  
Thermally Induced ◽  
Solar Heat ◽  
Ground Experiment ◽  
Thin Walled ◽  
Solar Heat Flux ◽  
The Impact ◽  
Transient Heat Flux

The spacecraft with large flexible space structures may be subject to the thermally induced vibration (TIV) due to the rapidly changed solar heat flux when it enters and leaves the eclipse, which would lead to certain spacecraft failure. This paper reports a laboratory experiment that aims to study the impact of transient characteristics of heat flux on the ground experiment of TIV. In the experiments on the TIV of a slender thin-walled beam, two different methods of providing transient heat flux were considered, and the process of entering and leaving eclipse was simulated, respectively. The experimental results demonstrate that different transient characteristics of heat flux will have large impact on the TIV of the specimen, and the ideal theoretical estimation of thermal characteristic time has limitations in practical engineering. In addition, it is found that the traditional way of simulating solar heat flux by turning on/off infrared heat lamps is not suitable for the TIV ground experiment. Instead, a transient heat flux simulation method by moving the baffle is recommended.

Natural-Ventilation Flow in a 3-D Room Fitted With Solar Chimney

2012 ◽  
Author(s):  
B. P. Huynh
Keyword(s):  
Heat Flux ◽  
Flow Pattern ◽  
Natural Ventilation ◽  
Air Flow ◽  
Ventilation Rate ◽  
High Heat Flux ◽  
Solar Chimney ◽  
Solar Heat ◽  
Solar Heat Flux ◽  
Inlet Opening

Natural-ventilation flow induced in a real-sized rectangular-box room fitted with a solar chimney on its roof is investigated numerically, using a commercial CFD (Computational Fluid Dynamics) software package. The chimney in turn is in the form of a parallel channel with one plate being subjected to uniform solar heat flux. Ventilation rate and air-flow pattern through the room are considered in terms of the heat flux for two different locations of the room’s inlet opening. Chien’s turbulence model of low-Reynolds-number K-ε is used in a Reynolds-Averaged Navier-Stokes (RANS) formulation. It is found that ventilation flow rate increases quickly with solar heat flux when this flux is low, but more gradually at higher flux. At low heat flux, ventilation rate is not significantly affected by location of the inlet opening to the room. On the other hand, at high heat flux, ventilation rate varies substantially with the opening’s location. Location of the inlet opening to the room also affects strongly the air-flow pattern. In any case, ample ventilation rate is readily induced by the chimney.

scholarly journals Development and assessment of a low cost sensor for solar heat flux measurements in buildings

Solar Energy ◽  
2015 ◽  
Vol 122 ◽  
pp. 795-803 ◽  
Author(s):  
Jean-Michel Dussault ◽  
Christian Kohler ◽  
Howdy Goudey ◽  
Robert Hart ◽  
Louis Gosselin ◽  
...  
Keyword(s):  
Heat Flux ◽  
Low Cost ◽  
Solar Heat ◽  
Flux Measurements ◽  
Solar Heat Flux

scholarly journals Simulated Seasonal and Interannual Variability of the Mixed Layer Heat Budget in the Northern Indian Ocean*

2007 ◽  
Vol 20 (13) ◽  
pp. 3249-3268 ◽  
Author(s):  
Clémentde Boyer Montégut ◽  
Jérôme Vialard ◽  
S. S. C. Shenoi ◽  
D. Shankar ◽  
Fabien Durand ◽  
...  
Keyword(s):  
Heat Flux ◽  
Indian Ocean ◽  
Interannual Variability ◽  
Latent Heat Flux ◽  
Mixed Layer ◽  
Heat Budget ◽  
Northern Indian Ocean ◽  
Solar Heat ◽  
Mixed Layer Heat Budget ◽  
Solar Heat Flux

Abstract A global ocean general circulation model (OGCM) is used to investigate the mixed layer heat budget of the northern Indian Ocean (NIO). The model is validated against observations and shows fairly good agreement with mixed layer depth data in the NIO. The NIO has been separated into three subbasins: the western Arabian Sea (AS), the eastern AS, and the Bay of Bengal (BoB). This study reveals strong differences between the western and eastern AS heat budget, while the latter basin has similarities with the BoB. Interesting new results on seasonal time scales are shown. The penetration of solar heat flux needs to be taken into account for two reasons. First, an average of 28 W m−2 is lost beneath the mixed layer over the year. Second, the penetration of solar heat flux tends to reduce the effect of solar heat flux on the SST seasonal cycle in the AS because the seasons of strongest flux are also seasons with a thin mixed layer. This enhances the control of SST seasonal variability by latent heat flux. The impact of salinity on SST variability is demonstrated. Salinity stratification plays a clear role in maintaining a high winter SST in the BoB and eastern AS while not in the western AS. The presence of freshwater near the surface allows heat storage below the surface layer that can later be recovered by entrainment warming during winter cooling (with a winter contribution of +2.1°C in the BoB). On an interannual time scale, the eastern AS and BoB are strongly controlled by the winds through the latent heat flux anomalies. In the western AS, vertical processes, as well as horizontal advection, contribute significantly to SST interannual variability, and the wind is not the only factor controlling the heat flux forcing.

The Modeling of Constant/Variable Solar Heat Flux Into a Porous Coil With Concentrator

2019 ◽  
Vol 142 (1) ◽  
Author(s):  
Sayyed Aboozar Fanaee ◽  
Mojtaba Rezapour
Keyword(s):  
Heat Flux ◽  
Heat Fluxes ◽  
The Finite Element Method ◽  
Governing Equations ◽  
Solar Heat ◽  
Clear Sky ◽  
Alumina Nanofluid ◽  
Solar Heat Flux ◽  
The City ◽  
Acceptable Agreement

In this paper, thermal-fluid modeling of nonporous/porous thermal coil filled by alumina nanofluid is discussed considering constant/variable solar heat fluxes. The fluxes are calculated for a parabolic concentrator at the solar paths for the city with a longitude of 59.20 deg and latitude of 32.87 deg in the clear sky at spring season. The governing equations are included as continuity, momentum, and energy conservations with considering variable solar flux by shadow effects of the coil on the parabolic concentrator. The numerical model is based on the finite element method by LU algorithm using the mumps solver. The results show that, in a porous medium, that the normalized temperature of the presented model has an acceptable agreement with experimental data with maximum errors of 3%. The existence of porosity significantly increases heat transfer parameters that improve transferred solar heat from the wall of the coil to nanofluid. The variable solar heat flux increases the temperature in the length of the coil rather than constant heat fluxes because of increasing exchanged heat to nanofluid.

scholarly journals Biomass gasification under high solar heat flux: Experiments on thermally thick samples

Fuel ◽  
2016 ◽  
Vol 174 ◽  
pp. 257-266 ◽  
Author(s):  
Victor Pozzobon ◽  
Sylvain Salvador ◽  
Jean Jacques Bézian
Keyword(s):  
Heat Flux ◽  
Biomass Gasification ◽  
Solar Heat ◽  
Solar Heat Flux
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