scholarly journals Study on Total Heat Flux of River Water and Its Approximate Value

1983 ◽  
Vol 27 ◽  
pp. 207-212
Keyword(s):  
Heat Flux ◽  
River Water ◽  
Total Heat ◽  
Total Heat Flux

Aero-Thermal Investigation of Tip Leakage Flow in a Film Cooled Industrial Turbine Rotor

2008 ◽  
Author(s):  
S. K. Krishnababu ◽  
H. P. Hodson ◽  
G. D. Booth ◽  
G. D. Lock ◽  
W. N. Dawes
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Mass Flow ◽  
Turbine Rotor ◽  
Total Heat ◽  
Leakage Flow ◽  
Total Heat Flux ◽  
Tip Leakage Flow ◽  
Tip Leakage ◽  
Flow And Heat Transfer

A numerical investigation of the flow and heat transfer characteristics of tip leakage in a typical film cooled industrial gas turbine rotor is presented in this paper. The computations were performed on a rotating domain of a single blade with a clearance gap of 1.28% chord in an engine environment. This standard blade featured two coolant and two dust holes, in a cavity-type tip with a central rib. The computations were performed using CFX 5.6, which was validated for similar flow situations by Krishnababu et al., [18]. These predictions were further verified by comparing the flow and heat transfer characteristics computed in the absence of coolant ejection with computations previously performed in the company (SIEMENS) using standard in-house codes. Turbulence was modelled using the SST k-ω turbulence model. The comparison of calculations performed with and without coolant ejection has shown that the coolant flow partially blocks the tip gap, resulting in a reduction of the amount of mainstream leakage flow. The calculations identified that the main detrimental heat transfer issues were caused by impingement of the hot leakage flow onto the tip. Hence three different modifications (referred as Cases 1 to 3) were made to the standard blade tip in an attempt to reduce the tip gap exit mass flow and the associated impingement heat transfer. The improvements and limitations of the modified geometries, in terms of tip gap exit mass flow, total area of the tip affected by the hot flow and the total heat flux to the tip, are discussed. The main feature of the Case 1 geometry is the removal of the rib and this modification was found to effectively reduce both the total area affected by the hot leakage flow and total heat flux to the tip while maintaining the same leakage mass flow as the standard blade. Case 2 featured a rearrangement of the dust holes in the tip which, in terms of aero-thermal-dynamics, proved to be marginally inferior to Case 1. Case 3, which essentially created a suction-side squealer geometry, was found to be inferior even to the standard cavity tip blade. It was also found that the hot spots which occur in the leading edge region of the standard tip and all modifications contributed significantly to the area affected by the hot tip leakage flow and the total heat flux.

scholarly journals Round robin study of total heat flux gauge calibration at fire laboratories

2004 ◽  
Author(s):  
William M Pitts ◽  
Annageri V Murthy ◽  
John L deRis ◽  
Jean-Remy R Filtz ◽  
Kjell Nygard ◽  
...  
Keyword(s):  
Heat Flux ◽  
Round Robin ◽  
Total Heat ◽  
Total Heat Flux

scholarly journals Numerical Simulation of Thawing Process in Frozen Soil

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Zhaoyu Yan ◽  
Wei Pan ◽  
Junjie Fang ◽  
Zihui Liu
Keyword(s):  
Numerical Simulation ◽  
Heat Flux ◽  
Liquid Water ◽  
Minimum Temperature ◽  
Frozen Soil ◽  
Total Heat ◽  
Water Volume ◽  
Total Heat Flux ◽  
Volume Curve ◽  
Thawing Process

Permafrost has been thawing faster due to climate change which would release greenhouse gases, change the hydrological regimes, affect buildings above, and so on. It is necessary to study the thawing process of frozen soil. A water-heat coupling model for frozen soil thawing is established on Darcy’s law and Heat Transfer in Porous Media interfaces in Comsol Multiphysics 5.5. Three curves of total liquid water volume, minimum temperature, and total heat flux in the thawing process are obtained from a numerical simulation. The distributions of liquid water, temperature, and pressure based on time are simulated too. The liquid water distribution is consistent with the total liquid water volume curve. The temperature distribution is confirmed by the minimum temperature and total heat flux curve. The pressure distribution represents ice in the frozen soil that generates negative pressure during the melting process. The numerical simulation research in this article deepens the understanding of the internal evolution in the process of frozen soil thawing and has a certain reference value for subsequent experimental research and related applications.

scholarly journals A Combination of Spatial Domain Filters to Detect Surface Ocean Current from Multi-Sensor Remote Sensing Data

2022 ◽  
Vol 14 (2) ◽  
pp. 332
Author(s):  
Mohammed Abdul Athick AS ◽  
Shih-Yu Lee
Keyword(s):  
Heat Flux ◽  
Remote Sensing Data ◽  
Total Heat ◽  
Sea Surface ◽  
Ocean Current ◽  
Surface Currents ◽  
Total Heat Flux ◽  
Data Set ◽  
Surface Ocean ◽  
Natural Break

This research investigates the applicability of combining spatial filter’s algorithm to extract surface ocean current. Accordingly, the raster filters were tested on 80–13,505 daily images to detect Kuroshio Current (KC) on weekly, seasonal, and climatological scales. The selected raster filters are convolution, Laplacian, north gradient, sharpening, min/max, histogram equalization, standard deviation, and natural break. In addition, conventional data set of sea surface currents, sea surface temperature (SST), sea surface height (SSH), and non-conventional data such as total heat flux, surface density (SSD), and salinity (SSS) were employed. Moreover, controversial data on ocean color are included because very few studies revealed that chlorophyll-α is a proxy to SST in the summer to extract KC. Interestingly, the performance of filters is uniform and thriving for seasonal and on a climatological scale only by combining the algorithms. In contrast, the typical scenario of identifying Kuroshio signatures using an individual filter and by designating a value spectrum is inapplicable for specific seasons and data set. Furthermore, the KC’s centerlines computed from SST, SSH, total heat flux, SSS, SSD, and chlorophyll-α correlate with sea surface currents. Deviations are observed in the various segments of Kuroshio’s centerline extracted from heat flux, chlorophyll-α, and SSS flowing across Tokara Strait from northeast Taiwan to the south of Japan.

The ballistic jump of the total heat flux after ECRH switching on in the T-10 tokamak

2003 ◽  
Vol 46 (2) ◽  
pp. 319-335 ◽  
Author(s):  
V F Andreev ◽  
Yu N Dnestrovskij ◽  
M V Ossipenko ◽  
K A Razumova ◽  
A V Sushkov
Keyword(s):  
Heat Flux ◽  
Total Heat ◽  
Total Heat Flux

Wave-Coherent Air–Sea Heat Flux

2008 ◽  
Vol 38 (4) ◽  
pp. 788-802 ◽  
Author(s):  
Fabrice Veron ◽  
W. Kendall Melville ◽  
Luc Lenain
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Surface Wave ◽  
Momentum Transfer ◽  
Latent Heat ◽  
Heat Fluxes ◽  
Total Heat ◽  
Research Progress ◽  
Total Heat Flux ◽  
Wave Conditions

Abstract Air–sea fluxes of heat and momentum play a crucial role in weather, climate, and the coupled general circulation of the oceans and atmosphere. Much progress has been made to quantify momentum transfer from the atmosphere to the ocean for a wide range of wind and wave conditions. Yet, despite the fact that global heat budgets are now at the forefront of current research in atmospheric, oceanographic, and climate problems and despite the good research progress in recent years, much remains to be done to better understand and quantify air–sea heat transfer. It is well known that ocean-surface waves may support momentum transfer from the atmosphere to the ocean, but the role of the waves in heat transfer has been ambiguous and poorly understood. Here, evidence is presented that there are surface wave–coherent components of both the sensible and the latent heat fluxes. Presented here are data from three field experiments that show modulations of temperature and humidity at the surface and at 10–14 m above the surface, which are coherent with the surface wave field. The authors show that the phase relationship between temperature and surface displacement is a function of wind speed. At a 10–12-m elevation, a wave-coherent heat transfer of O(1) W m−2 is found, dominated by the latent heat transfer, as well as wave-coherent fractional contributions to the total heat flux (the sum of latent and sensible heat fluxes) of up to 7%. For the wind speeds and wave conditions of these experiments, which encompass the range of global averages, this wave contribution to total heat flux is comparable in magnitude to the atmospheric heat fluxes commonly attributed to the effects of greenhouse gases or aerosols. By analogy with momentum transfer, the authors expect the wave-coherent heat transfer to decay with height over scales on the order of k−1, where k is the characteristic surface wavenumber; therefore, it is also expected that measurements at elevations of O(10) m may underestimate the contribution of the wave-induced heat flux to the atmosphere.

Round robin study of total heat flux gauge calibration at fire laboratories

2006 ◽  
Vol 41 (6) ◽  
pp. 459-475 ◽  
Author(s):  
William M. Pitts ◽  
Annageri V. Murthy ◽  
John L. de Ris ◽  
Jean-Rémy Filtz ◽  
Kjell Nygård ◽  
...  
Keyword(s):  
Heat Flux ◽  
Round Robin ◽  
Total Heat ◽  
Total Heat Flux
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