Thermal radiation from carbon particles in a heated nitrogen gas flow

Based on an effective energy conversion method between flowing gas enthalpy and thermal radiation, a three-layered type of porous heat exchanger (PHE) has been proposed. The PHE has one high temperature (HT) and two heat recovery (HR1 and HR2) sections. In HT section, the enthalpy of gas flow converts to thermal radiation and the opposite process happens in HR1 and HR2. In each section, a 2-D rectangular porous medium which is assumed to be absorbing, emitting and scattering is presented. For theoretical analysis of the PHE, the gas and solid phases are considered in non-local thermal equilibrium and separate energy equations are used for these two phases. Besides, in the gas flow simulation, the Fluent code is used to obtain the velocity distribution in the PHE from inlet to outlet section. For thermal analysis of the PHE, the coupled energy equations for gas and porous layer at each section are numerically solved using the finite difference method. In the computation of radiative heat flux distribution, the radiative transfer equation (RTE) is solved by the discrete ordinates method (DOM). The effects of scattering albedo, optical thickness, particle size of porous medium and inlet gas temperature on the efficiency of PHE are explored. Numerical results show that this type of PHE has high efficiency especially when the porous layers have high optical thickness. The present results are compared with those reported theoretically by other investigators and reasonable agreement is found.

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A Comparative Study of Nitrogen Gas Flow Ratio Dependence on the Electrical Characteristics of Sputtered Titanium Nitride Gate Bulk Planar Metal–Oxide–Semiconductor Field-Effect Transistors and Fin-Type Metal–Oxide–Semiconductor Field-Effect Transistors

Japanese Journal of Applied Physics ◽

10.1143/jjap.48.05dc01 ◽

2009 ◽

Vol 48 (5) ◽

pp. 05DC01 ◽

Cited By ~ 20

Author(s):

Tetsuro Hayashida ◽

Yongxun Liu ◽

Takashi Matsukawa ◽

Kazuhiko Endo ◽

Shinich O'uchi ◽

...

Keyword(s):

Metal Oxide ◽

Field Effect ◽

Gas Flow ◽

Field Effect Transistors ◽

Metal Oxide Semiconductor ◽

Oxide Semiconductor ◽

Electrical Characteristics ◽

Flow Ratio ◽

Nitrogen Gas ◽

Gas Flow Ratio

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Semisolid Joining of Zinc AG40A Alloy by Partial Remelting and Mechanical Stirring

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.141-143.225 ◽

2008 ◽

Vol 141-143 ◽

pp. 225-230 ◽

Cited By ~ 4

Author(s):

A. Narimannezhad ◽

Hossein Aashuri ◽

Amir Hossein Kokabi ◽

Ali Khosravani ◽

M. Kiani ◽

...

Keyword(s):

Gas Flow ◽

Cast Alloy ◽

Weld Zone ◽

Heating System ◽

Air Entrapment ◽

Nitrogen Gas ◽

Globular Structure ◽

Ceramic Block ◽

Mechanical Stirring ◽

Weld Structure

A technique to achieve the globular weld structure using stirring the localized semisolid zone during butt-joining of zinc AG40A (Zamak-3) die cast alloy is reported. Since the semisolid temperature range of this alloy is very narrow, the accurate controlling of weld pool temperature must be considered. By presented process, globular microstructure of the weld zone can be achieved. Moreover the near weld zone would have the globular structure due to semisolid holding. A gas heating system was designed to heat up the nitrogen gas to desired temperature accurately. A heating element was embedded in a castable ceramic block while a stream of gas could pass closely around the hot element length. Hot nitrogen gas flow through a precise ceramic nozzle was used to create a localized semisolid pool. At this stage a fine stirrer was introduced into the weld seam in order to mix the two sides into a single uniform joint. Local mechanical properties of different zones show a good strength in the weld metal zone and heat affected zone by results of the shear punch tests and hardness tests. Air entrapment in the pool decreases by controlling the speed of substrate movement and stirrer rotation under the nozzle. The strengths of each zone show relative correspondence to the variation of the hardness values.

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Tribological and Corrosive Properties of Tin/AlN Multilayer Film

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.560-561.837 ◽

2012 ◽

Vol 560-561 ◽

pp. 837-841

Author(s):

Pu Hong Tang ◽

Jie Mao ◽

Chong You Feng

Keyword(s):

Corrosion Resistance ◽

Coefficient Of Friction ◽

Gas Flow ◽

Multilayer Film ◽

Corrosion Current ◽

Multilayer Films ◽

Nitrogen Gas ◽

Corrosion Properties ◽

Wear Rates ◽

The Coefficient Of Friction

TiN/AlN nanoscale multilayer films were deposited by pulsed laser ablation on silicon, with different argon and nitrogen gas flow rates. The total thickness of the TiN/AlN multilayer film was approximately 1μm. The friction and corrosion properties were studied by tribological and corrosive tests. In tribological tests, ball-on-disc was used to determine coefficients of friction and wear rates. The coefficient of friction against a Si3N4 ball varied considerably between films, as does the wear rate. The lowest coefficient of friction μ=0.97 was shown at sample 1, whereas the other three multilayer films were ranged from 1.0 to 1.5. In corrosion test, the anodic polarization characteristics were measured in a 3.5% NaCl solution at room temperature to examine the corrosion resistance. The potentiodynamic polarization measurements showed that for all the multilayer films the corrosion potential shift to higher values, and the corrosion current density decreased with increasing of nitrogen gas flow rate, which indicate a higher nitrogen partial pressures lead to a better corrosion resistance.

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