Numerical Investigation of an Induced Draft Air-Cooled Condenser Under Crosswind Conditions

2021 ◽  
Author(s):  
Daniel L. Louw ◽  
C. J. Meyer ◽  
S. J. van der Spuy
Keyword(s):  
Heat Transfer ◽  
Axial Flow ◽  
Transfer Model ◽  
Power Ratio ◽  
Reference Case ◽  
Disk Model ◽  
Primary Direction ◽  
The Mean ◽  
Multiple Reference ◽  
Porosity Model

Abstract This study numerically investigated the performance of a 64-fan induced draft Air-Cooled Condenser (ACC) subjected to crosswind conditions. An Actuator Disk Model (ADM) was used to model the axial flow fans and a combination of the Darcy-Forchheimer porosity model and the Effectiveness Number of Transfer Units (ε-NTU) heat transfer model were used to model the heat exchangers. Crosswind conditions were applied to the ACC model in multiple directions and multiple reference velocities, with the results compared to a reference case where no wind was present. The induced draft ACC attained a mean fan volumetric effectiveness of 1.065, a mean heat transfer effectiveness of 1.039 and a mean heat-to-power ratio of 120.6 when no crosswinds were present. At relatively high crosswind velocities of 9 m/s the mean volumetric effectiveness decreased by 10.1% from wind coming from the primary direction, and by 10.3% from wind coming from the secondary direction. Similarly, the mean heat transfer effectiveness decreased by 21.7% under primary cross-winds, and by 31.3% under secondary crosswinds. Finally, the heat-to-power ratio of the ACC decreased to 92.5 under primary crosswinds, and by 77.6 under secondary crosswinds.

Deviation Analysis on Flow and Heat Transfer Model of Large Air-Cooled Steam Condenser Unit

2013 ◽  
Vol 860-863 ◽  
pp. 656-662
Author(s):  
Yi Lv ◽  
Hui Zhang ◽  
Yu Jin Yue ◽  
Li Jun Yang ◽  
Xiao Dong Zhang
Keyword(s):  
Heat Transfer ◽  
Power Plants ◽  
Thermal Power ◽  
Large Diameter ◽  
Axial Flow ◽  
Internal Flow ◽  
Ambient Air ◽  
Transfer Model ◽  
Deviation Analysis ◽  
Flow And Heat Transfer

Many power plants adopt air-cooled condensers (ACC) with finned tubes, using ambient air to condense turbine exhaust steam. Each condenser unit is mainly composed of two heat transfer surfaces like A and large diameter axial flow fans driving air. In the study of environmental wind effects, etc, due to the condenser unit size is bigger, it is necessary to simplify the condenser unit internal flow and heat transfer calculation, but the deviations introduced by these simplifies failed to get enough attention. In view of one condenser unit, three kinds of flow and heat tansfer combinated model were respectively investigated. A computational fluid dynamics software (CFD) is used to solve the problem.Research priority is analyzing the deviations of internal flow and heat transfer features in the condenser unit according to the extracted datum. The study gives some useful informatin to the design of a thermal power plant with an ACC system.

A 50 kW Fluidized Bed High Temperature Solar Receiver: Heat Transfer Analysis

1988 ◽  
Vol 110 (4) ◽  
pp. 313-320 ◽  
Author(s):  
G. Flamant ◽  
D. Gauthier ◽  
C. Boudhari ◽  
Y. Flitris
Keyword(s):  
Heat Transfer ◽  
Fluidized Bed ◽  
Large Diameter ◽  
Pilot Scale ◽  
Heat Transfer Analysis ◽  
Transfer Model ◽  
Front Wall ◽  
Measured Efficiency ◽  
The Mean ◽  
Solar Receiver

A theoretical and experimental investigation of a pilot scale solar fluidized bed receiver is presented. Large diameter alumina particles were used. Experimental data with the bed in the temperature range of 550° C to 915° C (wall 740° C–1035° C) are compared with a simple model based on one parameter: the mean front wall temperature. At 950° C, the predicted efficiency is 73 percent and the measured efficiency is about 65 percent. In addition, unsteady behavior of the receiver is described by a simple heat transfer model.

scholarly journals Tip Clearance Effect on Heat Transfer and Leakage Flows on the Shroud-Wall Surface in an Axial Flow Turbine

1992 ◽  
Author(s):  
Masaya Kumada ◽  
Satoshi Iwata ◽  
Masakazu Obata ◽  
Osamu Watanabe
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Axial Flow ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Local Heat Transfer Coefficient ◽  
Tip Clearance ◽  
Wall Surface ◽  
The Mean

An axial flow turbine for a turbocharger is used as a test turbine, and the local heat transfer coefficient on the surface of the shroud is measured under uniform heat flux conditions. The nature of the tip clearance flow on the shroud surface and a flow pattern in the downstream region of the rotor blades are studied, and measurements are obtained by using a hot-wire anemometer in combination with a periodic multi-sampling and an ensemble averaging technique. Data are obtained under on- and off-design conditions. The effects of inlet flow angle, rotational speed and tip clearance on the local heat transfer coefficient are elucidated. The mean heat transfer coefficient is correlated with the tip clearance, and the mean velocity is calculated by the velocity triangle method for approximation. A leakage flow region exists in the downstream direction beyond the middle of the wall surface opposite the rotor blade, and a leakage vortex is recognized at the suction side near the trailing edge.

Tip Clearance Effect on Heat Transfer and Leakage Flows on the Shroud-Wall Surface in an Axial Flow Turbine

1994 ◽  
Vol 116 (1) ◽  
pp. 39-45 ◽  
Author(s):  
M. Kumada ◽  
S. Iwata ◽  
M. Obata ◽  
O. Watanabe
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Axial Flow ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Local Heat Transfer Coefficient ◽  
Tip Clearance ◽  
Wall Surface ◽  
The Mean

An axial flow turbine for a turbocharger is used as a test turbine, and the local heat transfer coefficient on the surface of the shroud is measured under uniform heat flux conditions. The nature of the tip clearance flow on the shroud surface and a flow pattern in the downstream region of the rotor blades are studied, and measurements are obtained by using a hot-wire anemometer in combination with a periodic multisampling and an ensemble-averaging technique. Data are obtained under on-and off-design conditions. The effects of inlet flow angle, rotational speed, and tip clearance on the local heat transfer coefficient are elucidated. The mean heat transfer coefficient is correlated with the tip clearance, and the mean velocity is calculated by the velocity triangle method for approximation. A leakage flow region exists in the downstream direction beyond the middle of the wall surface opposite the rotor blade, and a leakage vortex is recognized at the suction side near the trailing edge.

Toward an Improved Understanding of Effect of Linear Heat Input on Heat-Affected Zone Tempering in Temper Bead Welding

2016 ◽  
Author(s):  
Kaiwen Zhang ◽  
Jeffrey A. Enneking ◽  
Bennett B. Grimmett ◽  
Wei Zhang
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Affected Zone ◽  
Heat Input ◽  
Experimental Testing ◽  
Transfer Model ◽  
Power Ratio ◽  
Hardness Distribution ◽  
Micro Hardness ◽  
Linear Heat

In temper bead welding, the heat input from welding is purposefully utilized to temper the hard microstructure for improving toughness. An optimal temper bead welding requires careful control of heat input and bead placement. In this study, the effect of linear heat input on heat-affected zone (HAZ) tempering was studied by a combination of experimental testing and numerical modeling. Temper bead welding experiments were performed on SA-533 steel using three different heat inputs while keeping the power ratio constant. The extent of tempering in the HAZ was quantified using micro-hardness mapping. A 2-D weld heat transfer model, using the double-ellipsoidal heat flux equation, was developed to calculate the temperature evolution. The peak temperatures experienced in the substrate’s HAZ was correlated to the hardness distribution. The results indicate that the linear heat input can have a significant influence on the extent of tempering in temper bead welding.

Theoretical Post-Dryout Heat Transfer Model

2018 ◽  
Vol 1 (1) ◽  
pp. 142-150
Author(s):  
Murat Tunc ◽  
Ayse Nur Esen ◽  
Doruk Sen ◽  
Ahmet Karakas
Keyword(s):  
Heat Transfer ◽  
Droplet Diameter ◽  
Heat Transfer Model ◽  
Transfer Model ◽  
Operating Pressure ◽  
Vertical Pipe ◽  
Two Phase ◽  
Experimental Values ◽  
Reactor Operating ◽  
Coolant System

A theoretical post-dryout heat transfer model is developed for two-phase dispersed flow, one-dimensional vertical pipe in a post-CHF regime. Because of the presence of average droplet diameter lower bound in a two-phase sparse flow. Droplet diameter is also calculated. Obtained results are compared with experimental values. Experimental data is used two-phase flow steam-water in VVER-1200, reactor coolant system, reactor operating pressure is 16.2 MPa. On heater rod surface, dryout was detected as a result of jumping increase of the heater rod surface temperature. Results obtained display lower droplet dimensions than the experimentally obtained values.

An Engine Heat Transfer Model for Comprehensive Thermal Simulations

2006 ◽  
Author(s):  
Filip Kitanoski ◽  
Wolfgang Puntigam ◽  
Martin Kozek ◽  
Josef Hager
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Model ◽  
Transfer Model ◽  
Thermal Simulations
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