ESTABLISHMENT OF NUMERICAL MODEL TO INVESTIGATE HEAT TRANSFER AND FLOW CHARACTERISTICS BY USING SCALE MODEL OF VESSEL COOLING SYSTEM FOR HTTR

2019 ◽  
Vol 2019.27 (0) ◽  
pp. 2330
Author(s):  
Shoji TAKADA ◽  
I Wayan NGARAYANA ◽  
Yukihiro NAKATSURU ◽  
Atsuhiko TERADA ◽  
Kenta MURAKAMI ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Numerical Model ◽  
Cooling System ◽  
Flow Characteristics ◽  
Scale Model ◽  
Investigate Heat Transfer

scholarly journals Establishment of reasonable 2-D model to investigate heat transfer and flow characteristics by using scale model of vessel cooling system for HTTR

2020 ◽  
Vol 7 (3) ◽  
pp. 19-00536-19-00536
Author(s):  
Shoji TAKADA ◽  
I Wayan NGARAYANA ◽  
Yukihiro NAKATSURU ◽  
Atuhiko TERADA ◽  
Kenta MURAKAMI ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Cooling System ◽  
Flow Characteristics ◽  
Scale Model ◽  
D Model ◽  
Investigate Heat Transfer

scholarly journals Full Surface Heat Transfer Characteristics of Stator Ventilation Duct of a Turbine Generator

2020 ◽  
Author(s):  
Shinyoung Jeon ◽  
Changmin Son ◽  
Jangsik Yang
Keyword(s):  
Heat Transfer ◽  
Cooling System ◽  
Cross Flow ◽  
Surface Heat ◽  
Operating Conditions ◽  
Scale Model ◽  
Turbine Generator ◽  
Surface Heat Transfer ◽  
Ventilation Duct ◽  
Flow Case

Turbine generator operates with complex cooling system due to the challenge in controlling the peak temperature of the stator bar caused by ohm loss, which is unavoidable. Therefore, it is important to characterise and quantifies the thermal performance of the cooling system. The focus of the present research is to investigate the heat transfer and pressure loss characteristics of typical cooling system, so-called stator ventilation duct. A real scale model was built at its operating conditions for the present study. The direction of cooling air is varied to consider its operation condition, so that there are (1) outward flow and (2) inward flow cases. In addition, the effect of (3) cross flow (inward with cross flow case) is also studied. The transient heat transfer method using thermochromic liquid crystals is implemented to measure full surface heat transfer distribution. A series of Computational Fluid Dynamics analysis is also conducted to support the observation from the experiment. For the inward flow case, the results suggest that the average Nusselt number of the 2nd duct is about 30% higher than the 3rd duct. The trend is similar with the effect of cross flow. The CFD results are in good agreement with the experimental data.

scholarly journals Enhanced heat transfer characteristics of conjugated air jet impingement on a finned heat sink

2017 ◽  
Vol 21 (1 Part A) ◽  
pp. 279-288 ◽  
Author(s):  
Shuxia Qiu ◽  
Peng Xu ◽  
Liping Geng ◽  
Arun Mujumdar ◽  
Zhouting Jiang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Heat Sink ◽  
Heat Transfer Performance ◽  
Cooling System ◽  
Flow Characteristics ◽  
Jet Impingement ◽  
Transfer Performance ◽  
Transfer Enhancement ◽  
Air Jet

Air jet impingement is one of the effective cooling techniques employed in micro-electronic industry. To enhance the heat transfer performance, a cooling system with air jet impingement on a finned heat sink is evaluated via the computational fluid dynamics method. A two-dimensional confined slot air impinging on a finned flat plate is modeled. The numerical model is validated by comparison of the computed Nusselt number distribution on the impingement target with published experimental results. The flow characteristics and heat transfer performance of jet impingement on both of smooth and finned heat sinks are compared. It is observed that jet impingement over finned target plate improves the cooling performance significantly. A dimensionless heat transfer enhancement factor is introduced to quantify the effect of jet flow Reynolds number on the finned surface. The effect of rectangular fin dimensions on impingement heat transfer rate is discussed in order to optimize the cooling system. Also, the computed flow and thermal fields of the air impingement system are examined to explore the physical mechanisms for heat transfer enhancement.

The Effect of Initial Cross Flow on the Cooling Performance of a Narrow Impingement Channel

2005 ◽  
Vol 127 (4) ◽  
pp. 358-365 ◽  
Author(s):  
Andrew C. Chambers ◽  
David R. H. Gillespie ◽  
Peter T. Ireland ◽  
Geoffrey M. Dailey
Keyword(s):  
Heat Transfer ◽  
Large Scale ◽  
Heat Transfer Performance ◽  
Cooling System ◽  
Cross Flow ◽  
Scale Model ◽  
Transfer Performance ◽  
Test Technique ◽  
Turbine Blade Cooling ◽  
Turbine Cooling

Impingement channels are often used in turbine blade cooling configurations. This paper examines the heat transfer performance of a typical integrally cast impingement channel. Detailed heat transfer coefficient distributions on all heat transfer surfaces were obtained in a series of low temperature experiments carried out in a large-scale model of a turbine cooling system using liquid crystal techniques. All experiments were performed on a model of a 19-hole, low aspect ratio impingement channel. The effect of flow introduced at the inlet to the channel on the impingement heat transfer within the channel was investigated. A novel test technique has been applied to determine the effect of the initial cross flow on jet penetration. The experiments were performed at an engine representative Reynolds number of 20,000 and examined the effect of additional initial cross flow up to 10 percent of the total mass flow. It was shown that initial cross flow strongly influenced the heat transfer performance with just 10 percent initial cross flow able to reduce the mean target plate jet effectiveness by 57 percent.

Heat Transfer and Fluid Flow Characteristic of One Side Heated Vertical Rectangular Channel That Inserted Thin Metallic Wire

2020 ◽  
Author(s):  
Gota Suga ◽  
Tetsuaki Takeda
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
High Temperature ◽  
Natural Convection ◽  
Cooling System ◽  
Copper Wire ◽  
Rectangular Channel ◽  
Flow Characteristics ◽  
Experimental Apparatus ◽  
High Temperature Reactor

Abstract A Very High Temperature Reactor (VHTR) is one of the next generation nuclear systems. From a view point of safety characteristics, a passive cooling system should be designed as the best way of a reactor vessel cooling system (VCS) in the VHTR. Therefore, the gas cooling system with natural circulation is considered as a candidate for the VCS of the VHTR. Japan Atomic Energy Agency (JAEA) is advancing the technology development of the VHTR and is now pursuing design and development of commercial systems such as the 300MWe gas turbine high temperature reactor GTHTR300C (Gas Turbine High Temperature Reactor 300 for Cogeneration). In the VCS of the GTHTR300C, many rectangular flow channels are formed around the reactor pressure vessel (RPV), and a cooling panel utilizing natural convection of air has been proposed. In order to apply the proposed panel to the VCS of the GTHTR300C, it is necessary to clarify the heat transfer and flow characteristics of the proposed channel in the cooling panel. Thus, we carried out an experiment to investigate heat transfer and fluid flow characteristics by natural convection in a vertical rectangular channel heated on one side. Experiments were also carried out to investigate the heat transfer and fluid flow characteristics by natural convection when a porous material with high porosity is inserted into the channel. An experimental apparatus is a vertical rectangular flow channel with a square cross section in which one surface is heated by a rubber heater. Dimensions of the experimental apparatus is 600 mm in height and 50 mm on one side of the square cross section. Air was used as a working fluid and fine copper wire (diameter: 0.5 mm) was used as a porous material. The temperature of the wall surface and gas in the channel were measured by K type thermocouples. We measured the outlet flow rate by hot-wire anemometer which is an omnidirectional spherical probe of diameter 2.5mm. The experiment has been carried out under the condition that a copper wire with a scourer model and a cubic lattice model were inserting into the channel.

Cooling Performance of a Narrow Impingement Channel Including the Introduction of Cross Flow Upstream of the First Hole

2003 ◽  
Author(s):  
Andrew C. Chambers ◽  
David R. H. Gillespie ◽  
Peter T. Ireland ◽  
Geoffrey M. Dailey
Keyword(s):  
Heat Transfer ◽  
Large Scale ◽  
Cooling System ◽  
Cross Flow ◽  
Scale Model ◽  
Test Technique ◽  
Turbine Blade Cooling ◽  
Turbine Cooling ◽  
Impingement Heat Transfer ◽  
Large Scale Model

Impingement channels are often used in turbine blade cooling configurations. This paper examines the heat transfer performance of a typical integrally cast impingement channel. Detailed heat transfer coefficient distributions on all heat transfer surfaces were obtained in a series of low temperature experiments carried out in a large-scale model of a turbine cooling system using liquid crystal techniques. All experiments were performed on a model of a 19-hole, low aspect ratio impingement channel. The effect of flow introduced at the inlet to the channel on the impingement heat transfer within the channel was investigated. A novel test technique has been applied to determine the effect of the initial cross flow on jet penetration. The experiments were performed at an engine representative Reynolds number of 20,000 and examined the effect of additional initial cross flow up to 10% of the total mass flow.

Heat Transfer and Fluid Flow Characteristics of One Side Heated Vertical Rectangular Channel Inserting Porous Material

2016 ◽  
Author(s):  
Takumi Shigematsu ◽  
Tetsuaki Takeda ◽  
Shumpei Funatani
Keyword(s):  
Heat Transfer ◽  
Porous Material ◽  
Cooling System ◽  
Natural Circulation ◽  
Rectangular Channel ◽  
Flow Characteristics ◽  
Vertical Channel ◽  
Passive Cooling ◽  
Fluid Flow Characteristics ◽  
Passive Cooling System

The Very High Temperature Reactor (VHTR) is a next generation nuclear reactor system. The passive cooling system should be designed for the VHTR as the best way of reactor vessel cooling system (VCS). Therefore, the gas cooling system with natural circulation is considered as a candidate for the VCS of the VHTR. Furthermore, we examined the heat transfer of rectangular vertical channel using “Spandrel” panel. “Spandrel” is the metallic plate having grooved patterns. The reason is that we can set it at low cost to the VCS because it is a kind of general construction materials. The objective of this study is to examine heat transfer characteristics of one side heated vertical rectangular channel with natural circulation and application of spandrel panel to the VCS of VHTR in order to construct the passive cooling system of the VHTR. We have performed an experiment and a numerical analysis. On experiment, we set the panel to adiabatic wall and supplied 100–400W/m2 heat flux to the panel. In order to obtain the heat transfer and fluid flow characteristics of a vertical channel inserting porous material, we have also carried out a numerical analysis using the commercial CFD code as the first step. From the results obtained in the analysis, it was found that the amount of heat removal was increased for 1–21% by inserting copper wires as porous material. This paper describes a thermal performance of the one-side heated vertical rectangular channel inserting copper wire with high porosity. From the view point of the economical and safety characteristic, the passive cooling system should be designed for the VTHR as the best way of the system. So, the gas cooling system by natural convection is the one of candidate system.

Heat Transfer and Flow Characteristics of an Engine Representative Impingement Cooling System

2000 ◽  
Vol 123 (1) ◽  
pp. 154-160 ◽  
Author(s):  
Changmin Son ◽  
David Gillespie ◽  
Peter Ireland ◽  
Geoffrey M. Dailey
Keyword(s):  
Heat Transfer ◽  
Liquid Crystal ◽  
Large Scale ◽  
Cooling System ◽  
Scale Model ◽  
Temperature Sensitive ◽  
Surface Shear Stress ◽  
Transfer Coefficients ◽  
Surface Shear ◽  
Impingement Cooling

A study of a large-scale model of an engine representative impingement cooling system has been performed. A series of tests were carried out to characterize the behavior of the system fully. These included cold flow diagnostic tests to determine the pressure loss and the static pressure distribution, and flow visualization to assess surface shear. The surface shear stress pattern provided by multiple stripes of colored paint applied to the target surface yielded important information on the near-wall flow features far from the jet axis. The row solved flow and pressure distributions are compared to industry standard predictions. Heat transfer tests using the transient liquid crystal technique were also conducted using coatings comprised of a mixture of three thermochromic liquid crystals. Analysis of the thermochromic liquid crystal data was enhanced by recent developments in image processing. In addition, an energy balance analysis of signals from fast-response thermocouples for air temperature measurement was applied to verify the levels of heat transfer coefficients on surfaces not coated with the temperature-sensitive liquid crystal.

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