Thermohydraulic characteristics of coolant gas flow through a control rod channel in a very high temperature gas cooled reactor

When a thermocouple is placed in a high temperature gas-flow stream, the measured temperature could be biased from the true gas temperature due to a large radiation heat transfer from a thermocouple surface to its surroundings. In this study, two thermocouples of unequal diameters of 1/8 inch and 1/16 inch were used to correct the radiation effect. This method is called the reduced radiation error (RRE). The test results show that the radiation on the thermocouple sheath tubes is the source of the error in the gas temperature measurement, and the RRE method is very effective for radiation correction under negligible conditions with the conductive dissipation through the sheath tubes.

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DISPERSED PHASE VELOCITY IN A HIGH-TEMPERATURE GAS FLOW

High Temperature Material Processes An International Quarterly of High-Technology Plasma Processes ◽

10.1615/hightempmatproc.2019030506 ◽

2019 ◽

Vol 23 (4) ◽

pp. 319-328

Author(s):

Dmitry V. Nesterovich ◽

Oleg G. Penyazkov ◽

Yu. A. Stankevich ◽

M. S. Tretyak ◽

Vladimir V. Chuprasov ◽

...

Keyword(s):

High Temperature ◽

Phase Velocity ◽

Gas Flow ◽

Dispersed Phase ◽

High Temperature Gas

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Analysis of the hot gas flow in the outlet plenum of the very high temperature reactor using coupled RELAP5-3D system code and a CFD code

Nuclear Engineering and Design ◽

10.1016/j.nucengdes.2007.06.008 ◽

2008 ◽

Vol 238 (1) ◽

pp. 274-279 ◽

Cited By ~ 22

Author(s):

Nolan Anderson ◽

Yassin Hassan ◽

Richard Schultz

Keyword(s):

High Temperature ◽

Gas Flow ◽

Hot Gas ◽

Very High Temperature Reactor ◽

High Temperature Reactor ◽

Very High

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Comparative Study of GaN Growth Process by MOVPE

MRS Proceedings ◽

10.1557/proc-572-463 ◽

1999 ◽

Vol 572 ◽

Author(s):

Jingxi Sun ◽

J. M. Redwing ◽

T. F. Kuech

Keyword(s):

High Temperature ◽

Comparative Study ◽

Gas Phase ◽

Residence Time ◽

Gas Flow ◽

Flow Sheet ◽

Flow Zone ◽

High Quality ◽

Phase Temperature ◽

High Temperature Gas

ABSTRACTA comparative study of two different MOVPE reactors used for GaN growth is presented. Computational fluid dynamics (CFD) was used to determine common gas phase and fluid flow behaviors within these reactors. This paper focuses on the common thermal fluid features of these two MOVPE reactors with different geometries and operating pressures that can grow device-quality GaN-based materials. Our study clearly shows that several growth conditions must be achieved in order to grow high quality GaN materials. The high-temperature gas flow zone must be limited to a very thin flow sheet above the susceptor, while the bulk gas phase temperature must be very low to prevent extensive pre-deposition reactions. These conditions lead to higher growth rates and improved material quality. A certain range of gas flow velocity inside the high-temperature gas flow zone is also required in order to minimize the residence time and improve the growth uniformity. These conditions can be achieved by the use of either a novel reactor structure such as a two-flow approach or by specific flow conditions. The quantitative ranges of flow velocities, gas phase temperature, and residence time required in these reactors to achieve high quality material and uniform growth are given.

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High Temperature Stability of MGCs Gas Turbine Components in Air and Combustion Gas Flow Environments

Volume 2: Turbo Expo 2004 ◽

10.1115/gt2004-53573 ◽

2004 ◽

Cited By ~ 2

Author(s):

Narihito Nakagawa ◽

Hideki Ohtsubo ◽

Kohji Shibata ◽

Atsuyuki Mitani ◽

Kazutoshi Shimizu ◽

...

Keyword(s):

High Temperature ◽

Gas Turbine ◽

Gas Flow ◽

Temperature Stability ◽

High Temperature Strength ◽

High Temperature Stability ◽

Combustion Gas ◽

Air Atmosphere ◽

Low Nox Emission ◽

Very High

Melt growth composites (MGCs) have a unique microstructure, in which continuous networks of single-crystal phases interpenetrate without grain boundaries. Therefore, the MGCs have excellent high-temperature strength characteristics, creep resistance, oxidation resistance and thermal stability in an air atmosphere at very high temperature. To achieve ultra-high thermal efficiency and low NOx emission for gas turbine systems, non-cooled turbine nozzle vanes and heat shield panels of combustor liners has been fabricated on an experimental basis. These components are thermally stable after heat treatment at 1700°C for 1000 hours in an air atmosphere. In addition, we have just started the exposure tests to evaluate the influence of combustion gas flow environment on MGCs.

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