A Thermal Model for Concentric-Tube Overfire Air Ports

2009 ◽  
Vol 1 (1) ◽  
Author(s):  
Larry W. Swanson ◽  
David K. Moyeda
Keyword(s):  
Heat Source ◽  
Wall Temperature ◽  
Tube Wall ◽  
Operating Conditions ◽  
Transfer Model ◽  
Radiation Boundary Condition ◽  
Temperature Distributions ◽  
Airflow Distribution ◽  
Highly Nonlinear ◽  
Tube Wall Temperature

A quasisteady multimode heat-transfer model for boiler concentric-tube overfire air ports has been developed that predicts the effect of geometry, furnace heat source and heat sink temperatures, axial injector wall conduction, and coolant flow rate on the tube wall temperature distributions. The model imposes a radiation boundary condition at the outlet tip of the ports, which acts as a heat source. The model was validated using field data and showed that both the airflow distribution in the ports and tube diameter can be used to control the maximum tube wall temperature. This helps avoid tube overheating and thermal degradation. For nominal operating conditions, highly nonlinear axial temperature distributions were observed in both tubes near the hot outlet end of the port.

A Thermal Model for Concentric-Tube Overfire Air Ports

2003 ◽  
Author(s):  
L. W. Swanson ◽  
D. K. Moyeda ◽  
B. A. Folsom
Keyword(s):  
Heat Source ◽  
Wall Temperature ◽  
Tube Wall ◽  
Operating Conditions ◽  
Transfer Model ◽  
Radiation Boundary Condition ◽  
Temperature Distributions ◽  
Airflow Distribution ◽  
Highly Nonlinear ◽  
Tube Wall Temperature

A quasi-steady multi-mode heat-transfer model for boiler concentric-tube overfire air ports has been developed that predicts the effect of geometry, furnace heat source and heat sink temperatures, axial injector wall conduction, and coolant flow rate on the tube wall temperature distributions. The model imposes a radiation boundary condition at the outlet tip of the ports, which acts as a heat source. The model was validated using field data and showed that both the airflow distribution in the ports and tube diameter can be used to control the maximum tube wall temperature. This helps avoid tube overheating and thermal degradation. For nominal operating conditions, highly nonlinear axial temperature distributions were observed in both tubes near the hot outlet end of the port.

A Thermal Model for Reburning Fuel Injectors in Glass Furnaces

2000 ◽  
Author(s):  
L. W. Swanson ◽  
R. R. Koppang
Keyword(s):  
Temperature Distribution ◽  
Heat Source ◽  
Wall Temperature ◽  
Operating Conditions ◽  
Large Temperature ◽  
Transfer Model ◽  
Radiation Boundary Condition ◽  
Fuel Injectors ◽  
Highly Nonlinear ◽  
Glass Furnaces

Abstract A quasi-steady multi-mode heat-transfer model for retraining fuel injectors in glass furnaces has been developed that predicts the effect of geometry, furnace heat source and heat sink temperatures, radial and axial injector wall conduction, and coolant flow rate on the injector wall temperature distribution. The model imposes a radiation boundary condition at the outlet tip of the injector, which acts as a heat source. A parametric study has been conducted to investigate effects that the furnace gas temperature, reburning methane fuel and purge-air flow rates, and furnace wall temperature have on the injector wall temperature distribution. For nominal operating conditions, highly nonlinear temperature distributions were observed throughout the injector. Operation with methane as the coolant produced an extremely large temperature gradient near the injector tip that could cause excessive thermal stresses in the injector wall. The results also showed that nominal injector operating conditions should prevent alkali deposition at the injector tip and produce injector/metallic disconnect temperatures well below the initial deformation temperature for stainless steel.

Eexperimental Investigation of Heat Characteristics of Liquid Flow With Micro-Encapsulated Phase Change Material

2008 ◽  
Author(s):  
Rami Sabbah ◽  
Jamal Yagoobi ◽  
Said Al Hallaj
Keyword(s):  
Heat Transfer ◽  
Phase Change ◽  
Phase Change Material ◽  
Wall Temperature ◽  
Tube Wall ◽  
Operating Conditions ◽  
Working Fluid ◽  
Tube Wall Temperature ◽  
Encapsulated Phase Change Material ◽  
Change Material

This experimental study investigates the effect of presence of Micro-Encapsulated Phase Change Material (MEPCM) within the working fluid on thermal performances of the cooling system. To conduct this study, an experimental setup consisting of a steel tube with an inner diameter of 4.3mm, outer diameter of 6.3mm and a length of 1,016mm is selected. 5%, 10% and 20% mass concentration MEPCM slurries with particle diameter ranging between 5–15μm were included in this study. Tube wall temperature profile, fluid inlet, outlet temperatures, the pressure drop across the tube are measured and corresponding heat transfer coefficients are determined for various operating conditions. Differential Scanning Calometery (DSC) test results for an iterative method for local variables calculation. The experimental results showed significant enhancement in heat transfer coefficient higher than 50% and reduction in tube wall temperature higher than 35%. The controlling parameters are identified and their effects on the heat transfer characteristics are evaluated and analyzed.

scholarly journals Fouling in a Steam Cracker Convection Section Part 1: A Hybrid CFD-1D Model to Obtain Accurate Tube Wall Temperature Profiles

2019 ◽  
Vol 41 (2) ◽  
pp. 127-137 ◽  
Author(s):  
Pieter Verhees ◽  
Abdul Rahman Akhras ◽  
Kevin M. Van Geem ◽  
Geraldine J. Heynderickx
Keyword(s):  
Wall Temperature ◽  
Tube Wall ◽  
Temperature Profiles ◽  
Tube Wall Temperature ◽  
1D Model ◽  
Steam Cracker

Heat Transfer Characteristics of Various Gun Barrels Under Different Operating Conditions

2019 ◽  
Author(s):  
Mohamed Gadalla ◽  
Muhammad Jasim ◽  
Omar Ahmad
Keyword(s):  
Heat Transfer ◽  
Thermal Management ◽  
Cross Section ◽  
Wall Temperature ◽  
Circular Cross Section ◽  
Typical Case ◽  
Operating Conditions ◽  
Firing Process ◽  
Transfer Model ◽  
Gun Barrel

Abstract The thermal stability parameter is an important parameter for predicting the lifespan of structures. In this paper, a two-dimensional transient heat transfer model of machine gun barrels undergoing continuous firing developed and analyzed for different geometries and thermal properties. The model for the transient thermal analysis is based on the forced convection heat transfer at the inner surface of the gun barrel. Finite element simulations were performed to predict the interior and exterior barrel temperature profiles and temperature contours after continuous firing process. The incomplete Cholesky Conjugate Gradient (ICCG) solver was adopted in solving unsymmetrical thermal transient analyses. The material thermal behavior studied for the basic circular cross section of gun barrels showed that the lowest inner wall temperature was for high rounds was achieved in steel barrels due to the rapid conducted and convective heat transfer to the environment. While the highest inner wall temperature was recorded for ceramic STK4 barrels and an increase of inner wall temperature by 17% was observed as compared to the typical case of circular cross section steel barrel. In general, a higher inner temperature in the gun barrel is undesirable and harm due to the possibility of reaching the cook-off scenario at earlier rounds. Results concluded that non-circular geometries with constrained cross section areas of typical case improve thermal management and the hexagonal geometry had the best thermal management and could provide more rounds for users. In addition, titanium barrels would have a weight drop of 41% while the overall barrel’s temperature increases by 49%.

Nozzle tube-wall temperature measurement by radiometric techniques.

1966 ◽  
Vol 3 (7) ◽  
pp. 1144-1146
Author(s):  
E. L. GEERY ◽  
W. R. THOMPSON ◽  
J. H. BEVERIDGE ◽  
W. J. HELM
Keyword(s):  
Temperature Measurement ◽  
Wall Temperature ◽  
Tube Wall ◽  
Tube Wall Temperature
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