Numerical Investigation of the Effect of Waste Heat Extracting Location on Temperature Distribution

2011 ◽  
Vol 354-355 ◽  
pp. 361-364
Author(s):  
Zhan Xu Tie ◽  
Hai Xia Li ◽  
Xiao Dian Guo
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Gas Flow ◽  
Waste Heat ◽  
Cement Clinker ◽  
Cement Kiln ◽  
Gas Temperature ◽  
Flow And Heat Transfer ◽  
Grate Cooler ◽  
High Temperature Gas

The numerical model was established to simulate the gas flow and heat transfer in cement grate cooler. It is useful to increase the gas temperature when the extracting exit position is close to the cement kiln end. The appropriate position of the extracting high temperature gas is about 5 m far away from the cement clinker inlet.

Computational Analysis of Gas Flow and Heat Transport Phenomena in Monolithic Structures for High Temperature Processes

2005 ◽  
Author(s):  
Faruk Selimovic ◽  
Tor Bruun ◽  
Bengt Sunde´n
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Power Density ◽  
Gas Flow ◽  
Gas Temperature ◽  
Oxidation Of Methane ◽  
Steam Methane ◽  
High Temperature Processes ◽  
Efficient Heat Transfer ◽  
Flow Maldistribution

High-temperature catalytic processes such as partial oxidation of Methane (POX) and steam Methane reforming (SMR) may benefit from use of reactor systems using monolithic honeycomb structures. Hereby, process performance is enhanced through more efficient heat transfer and considerable smaller reactor foot-prints than for conventional reactor concepts. Compact ceramic heat exchange structures may also be an interesting option for increasing the energy efficiency of high temperature processes in general. One example is single cycle turbines where these structures can be used as recuperators. The purpose of this paper is to describe modelling of gas flow pattern and heat transfer in reactors and heat exchangers with monolithic based structures. This technology is currently under development in a partnership of European companies and academia, with financial support from the EC and Swiss Government. The mathematical model developed for heat transfer and flow maldistribution has been used for counter-current checkerboard channel-arrangement. Pressure drop has been analyzed both experimentally and numerically (computation fluid dynamics, CFD). Power density has been shown to depend on various reactor parameters. Channel geometry, inlet gas temperature difference and channel wall thickness have been calculated to find the influence on power density.

Computational Fluid Dynamics Investigation of a High Temperature Waste Heat Exchanger Tube Sheet Assembly

2005 ◽  
Author(s):  
Michael A. Porter ◽  
Dennis H. Martens ◽  
Thomas Duffy ◽  
Sean McGuffie
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
High Temperature ◽  
Temperature Distribution ◽  
Carbon Steel ◽  
Gas Flow ◽  
Waste Heat ◽  
Thermal Reactor ◽  
Process Gas

Many modern Sulfur Recovery Unit (SRU) process waste heat recovery exchangers operate in high temperature environments. These exchangers are associated with the thermal reactor system where the tubesheet/tube/ferrule assemblies are exposed to gasses at temperatures approaching 3000°F. Because sulfur compounds are present in the process gas, the carbon steel tubesheet and tubes in the assembly will be deteriorated by sulfidation as the operating metal temperature rises above 600°F. Ferrule systems are used to protect the carbon steel from exposure to excessive temperatures. The temperature distribution in the steel tubesheet/tube/ferrule system is affected by process gas flow and heat transfer through the assembly. Rather than depend upon “assumed” heat transfer coefficients and fluid flow distribution, a Computational Fluid Dynamics (CFD) investigation was conducted to study the flow fields and heat transfer in the tubesheet assembly. It was found that the configuration of the ferrule installation has a large influence on the temperature distribution in the steel materials and, therefore, the possible sulfidation of the carbon steel parts.

scholarly journals Numerical Investigation on Radiation Effect in Transpiration Cooling

2021 ◽  
Vol 2097 (1) ◽  
pp. 012011
Author(s):  
Kang Qian ◽  
Taolue Liu ◽  
Fei He ◽  
Meng Wang ◽  
Longsheng Tang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Gas Flow ◽  
Radiation Effect ◽  
Porous Wall ◽  
Radiation Absorption ◽  
Transpiration Cooling ◽  
Coupled Modeling ◽  
High Temperature Gas ◽  
Numerical Strategy

Abstract This paper proposed a numerical strategy which could achieve the coupled modeling and solving of transpiration cooling with external high-temperature gas flow and especially take the radiation effect into account. Based on the numerical strategy, the heat and mass transfer characteristics of the transpiration cooling in a high-temperature gas channel were studied, and the radiation effect and corresponding influence factors were analyzed. The results indicated that the radiative heat flux takes an important role in the heat transfer between the transpiration cooling and external high-temperature gas flow which may reach 40% under the operating condition considered in this work, and the radiation absorption from the coolant is more obvious near the downstream wall. As the wall emissivity increases, the radiation heat transfer in the downstream area of the porous wall is enhanced significantly and thereby the wall temperature there increases, as the result, the uniformity of the temperature distribution on the whole porous wall is improved to some extent.

The UGKS Simulation of Microchannel Gas Flow and Heat Transfer Confined Between Isothermal and Nonisothermal Parallel Plates

2020 ◽  
Vol 142 (12) ◽  
Author(s):  
Lianfu Dai ◽  
Huiying Wu ◽  
Jun Tang
Keyword(s):  
Heat Transfer ◽  
Cross Section ◽  
Gas Flow ◽  
Flow Direction ◽  
Channel Height ◽  
Parallel Plates ◽  
Gas Temperature ◽  
Gas Velocity ◽  
Microscopic Mechanism ◽  
Flow And Heat Transfer

Abstract The unified gas kinetic scheme (UGKS) is introduced to simulate the near transition regime gas flow and heat transfer in microchannel confined between isothermal and nonisothermal parallel plates. The argon gas is used and its inlet Knudsen number (Knin) ranges from 0.0154 to 0.0715. It is found that: (1) both microchannel gas flows under isothermal and nonisothermal parallel plates display a trend of speed acceleration and temperature decrease along flow direction, for which the microscopic mechanism explanation is first proposed; (2) inlet gas streamlines under nonisothermal plates condition deviate from the parallel distributions under isothermal plates condition due to the dual driving effects of pressure drop along flow direction and temperature difference along cross section; (3) gas temperature, pressure, density and viscosity distributions along cross section under nonisothermal plates condition deviate from the parabolic distributions under isothermal plates condition, while the gas velocity keeps the parabolic distribution due to the effect of Knudsen layer; (4) as channel height increases or channel length and gas molecular mean free path decrease, the gas temperature distribution along cross section under nonisothermal plates condition tends to transition from linear to curve one due to the decreasing effect of heat transfer along cross section and increasing effect of gas acceleration along flow direction, this transition from linear to curve one becomes more obvious along flow direction. (5) the gas velocity under nonisothermal plates condition decreases with the increase of inlet gas temperature (Tin), lower plate temperature (Tl) and Knin, while the gas temperature increases with the increase of Tin, Tl and Knin.

Friction and Heat Transfer During Injection into a Near-Sonic High-Temperature Gas Flow in a Channel

1997 ◽  
Vol 28 (7-8) ◽  
pp. 438-445
Author(s):  
A. A. Vasil'yev ◽  
O. I. Didenko ◽  
V. F. Vishnyak ◽  
V. N. Panchenko
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Gas Flow ◽  
High Temperature Gas

Numerical Simulation of Accident Scenario in HTGR (Pebble Bed Reactor) Using COMSOL® Code

2013 ◽  
Author(s):  
Geoffrey J. Peter
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Computer Code ◽  
Pebble Bed ◽  
Pebble Bed Reactor ◽  
Accident Scenario ◽  
Flow And Heat Transfer ◽  
Custom Made ◽  
Accident Scenarios ◽  
High Temperature Gas

High Temperature Gas Cooled Reactor (HTGR) development and operation is expanding in the United Kingdom, Russia, USA (Generation IV Reactors), and France (Pebble Bed Modular Reactor, PBMR). A prototype pebble bed reactor producing 10 MW thermal, High Temperature Reactor (HTR-10) is in operation in China. However, the general public remains skeptical of the safety and the perceived dangers of possible accidents. Of particular concern are blockages caused by local variations in flow and heat transfer that lead to hot spots within the bed. This paper models the accident scenario resulting from blockages due to the retention of dust in the coolant gas or from the rupture of one or more fuel particles used in the High Temperature Gas Cooled (Pebble Bed) Nuclear Reactors using the commercially available computer code COMSOL. Numerical modeling of flow and heat transfer in a packed bed produces an Elliptical Non-Linear Partial Differential equation that requires custom made computer codes. Previously published results obtained from the use of a custom-made verified computer code are limited to one accident scenario and involve considerable modification to study different accident scenarios. Thus the use of a commercially available computer code that can simulate many different accident scenarios is of considerable advantage. Further, this paper compares numerical solutions obtained from custom-made computer code with COMSOL simulation and discusses the advantages and limitations of both codes.

Heat transfer in aerodynamic-tube nozzles with high-temperature gas flow

1978 ◽  
Vol 35 (6) ◽  
pp. 1466-1470
Author(s):  
N. I. Khvostov ◽  
V. E. Chekalin ◽  
A. D. Sukhobokov ◽  
K. N. Skirda
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Gas Flow ◽  
High Temperature Gas
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