scholarly journals Experimental Study of the Effect of Graphite Dispersion on the Heat Transfer Phenomena in a Reactor Cavity Cooling System

2012 ◽  
Vol 177 (2) ◽  
pp. 217-230 ◽  
Author(s):  
Rodolfo Vaghetto ◽  
Luigi Capone ◽  
Yassin A. Hassan
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Cooling System ◽  
Cavity Cooling

Study on the Heat Transfer in the Water Pool Type Reactor Cavity Cooling System of the Very High Temperature Gas Cooled Reactor

2005 ◽  
Author(s):  
H. K. Cho ◽  
D. U. Seo ◽  
M. O. Kim ◽  
G. C. Park
Keyword(s):  
Heat Transfer ◽  
Forced Convection ◽  
Cooling System ◽  
Reactor Vessel ◽  
Water Pool ◽  
Cooling Pipe ◽  
Cavity Cooling ◽  
The Heat Transfer Coefficient ◽  
Pool Type ◽  
High Temperature Gas

In the HTGR (High Temperature Gas Cooled Reactor), the Reactor Cavity Cooling System (RCCS) is equipped to remove the heat transferred from the reactor vessel to the structure of the containment. The function of the RCCS is to dissipate the heat from the reactor cavity during normal operation including shutdown. The system also removes the decay heat during the loss of forced convection (LOFC) accident. A new concept of the water pool type RCCS was proposed at Seoul National University. The system mainly consists of two parts, water pool located between the containment and reactor vessel and five trains of air cooling system installed in the water pool. In normal operations, the heat loss from the reactor vessel is transferred into the water pool via cavity and it is removed by the forced convection of air flowing through the cooling pipes. During the LOFC accident, the after heat is passively removed by the water tank without the forced convection of air and the RCCS water pool is designed to provide sufficient passive cooling capacity of the after heat removal for three days. In the present study, experiments and numerical calculations using CFX5.7 for the water pool and cooling pipe were performed to investigate the heat transfer characteristics and evaluate the heat transfer coefficient model of the MARS-GCR (Multi-dimensional Analysis of Reactor Safety for Gas Cooled Reactor Analysis) which was developed for the safety analysis of the gas cooled reactor. From the results of the experiments and CFX calculations, heat transfer coefficients inside the cooling pipe were calculated and those were used for the assessment for the heat transfer coefficient model of the MARS-GCR.

An Experimental Study of Impingement Heat Transfer on the Surfaces With Micro W-Shaped Ribs

2015 ◽  
Author(s):  
Yu Rao ◽  
Peng Chen ◽  
Jiaqi Zhu
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Flat Plate ◽  
Pressure Loss ◽  
Cooling System ◽  
Cross Flow ◽  
Jet Impingement ◽  
Test Plate ◽  
Plate Spacing ◽  
Impingement Heat Transfer

The paper proposed an idea of using micro-W-shaped ribs on a test plate to improve the impingement heat transfer performance in a multiple-jet impingement cooling system. An experimental study has been conducted on the heat transfer characteristics of multiple-jet impingement onto a flat plate and a roughened plate with micro W-shaped ribs under maximum cross flow scheme. Transient liquid crystal thermography method has been used to obtain the detailed impingement heat transfer distribution for the Reynolds numbers from 15,000 to 30,000.The effects of micro W ribs on the local Nusselt number and the related pressure loss were investigated experimentally. The jet-to-plate spacing H/d=1.5 was used in the experiments for both the flat and the micro-W-rib roughened plate. The experiments showed that the micro W ribs on the plate can enhance the impingement heat transfer globally and locally, and increase the heat transfer uniformity, which are due to the facts that the micro W ribs on the test plate increase the near-wall turbulent mixing by interacting with the wall jets and cross flow. The pressure loss is negligibly increased compared to the impingement onto the flat plate.

Experimental Study on Flow and Heat Transfer Characteristics in a Microscale Heat Exchanger

2007 ◽  
Author(s):  
Tao Wang ◽  
Xuegong Hu ◽  
Dawei Tang
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Heat Exchanger ◽  
Thermal Resistance ◽  
Flow Rate ◽  
Laser Cooling ◽  
Cooling System ◽  
Volumetric Flow Rate ◽  
Distilled Water ◽  
Total Thermal Resistance

To solve the questions of the middle heat exchanger of space-based laser cooling system such as large heat transfer area and operating mode instability, a MC-MG (Microchannel-Microgroove) microscale heat exchanger is proposed and experimental study is carried out. The experimental results indicate that as the Reynolds number increases, the Nusselt number originally increases and then keeps constant. While adding the volumetric flow rate of distilled water in the microchannels, the total thermal resistance is first reduced and then becomes steady. With increasing the volumetric flow rate of distilled water, the total quantity of heat transfer increases first, then decreases and finally tends to be constant. The average heat transfer coefficient of the heat exchanger reaches to 1.6 × 104W/ (m2-K) and total thermal resistance is less than 0.21K/W. Therefore the solution to cooling laser with the heat exchanger is preferable.

Experimental Investigation of Reactor Cavity Cooling System (RCCS) for a Very High Temperature Reactor (VHTR)

2010 ◽  
Author(s):  
L. Capone ◽  
C. E. Perez ◽  
Y. Hassan
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Surface Temperature ◽  
Temperature Profile ◽  
Cooling System ◽  
Experimental Facility ◽  
Very High Temperature Reactor ◽  
High Temperature Reactor ◽  
Cavity Cooling ◽  
Very High

The reactor cavity cooling system (RCCS) for a very high temperature reactor (VHTR) represents a very important safety feature for achieving the defense in depth of the plant. An experimental facility was built for testing the heat transfer capability and phenomenology of this last heat sink designed for ensuring the cooling down of structural material of the vessel and of the concrete walls of the vessel cavity. This small scale facility was built using some of the scaling laws in order to resemble the main heat transport features in RCCS configuration. The natural convection phenomena and radiative heat transfer inside the cavity were represented. The experimental facility represents half of the vessel and of the reactor cavity with five stand pipes for cavity cooling using water as cooling fluid. Measurements were performed heating up the vessel surface temperature to an average temperature of 300 °C that is the average value in accident scenarios. Temperature measurements of the vessel surface temperature, the outer pipes surface temperature profile and inlet and outlet temperature of the cooling water were performed. Axial and radial temperature profiles of the air in the cavity were measured using a movable rack of 24 thermocouples. The results demonstrated the natural circulation phenomena. In addition Velocity measurement of the air inside the cavity were performed using particle tracking velocimetry techniques (PTV) determining the flow regime characteristics and the coupling with the temperature profile. The experimental test matrix of various flow rates in the cooling pipes were carried out.

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