VENTILATION AIR CHANNEL METHODS AND USE OF THEIR OPPORTUNITIES

2015 ◽  
Author(s):  
Ladislav Tazky
Keyword(s):  
Air Channel

Local thermal non-equilibrium conjugate forced convection and entropy generation in an aircraft cabin with air channel partially filled porous insulation

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Oktay Çiçek ◽  
A. Cihat Baytaş
Keyword(s):  
Thermal Conductivity ◽  
Reynolds Number ◽  
Forced Convection ◽  
Cross Section ◽  
Entropy Generation ◽  
Channel Wall ◽  
Darcy Number ◽  
Content Type ◽  
Exit Cross Section ◽  
Air Channel

Purpose The purpose of this study is to numerically investigate heat transfer and entropy generation between airframe and cabin-cargo departments in an aircraft. The conjugate forced convection and entropy generation in a cylindrical cavity within air channel partly filled with porous insulation material as simplified geometry for airframe and cabin-cargo departments are considered under local thermal non-equilibrium condition. Design/methodology/approach The non-dimensional governing equations for fluid and porous media discretized by finite volume method are solved using the SIMPLE algorithm with pressure and velocity correction. Findings The effects of the following parameters on the problem are investigated; Reynolds number, Darcy number, the size of inlet and exit cross-section, thermal conductivity ratio for solid and fluid phases, angle between the vertical symmetry axis and the end of channel wall exit and the gap between adiabatic channel wall and horizontal adiabatic wall separating cabin and cargo sections. Originality/value This paper can provide a basic perspective and framework for thermal design between the fuselage and cabin-cargo sections. The minimum total entropy generation number is calculated for various Reynolds numbers and thermal conductivity ratios. It is observed that the channel wall temperature increases for high Reynolds number, low Darcy number, narrower exit cross-section and wider the gap between channel wall and horizontal.

Speech Compensation for Prosthodontically Created Palatal Asymmetries

1988 ◽  
Vol 31 (1) ◽  
pp. 48-53 ◽  
Author(s):  
Sandra L. Hamlet
Keyword(s):  
General Orientation ◽  
Air Channel

Symmetry of alveolar and palatal contour was altered prosthodontically for five subjects. There was palatographic evidence, for both/s/and/l/, that the prosthodontic changes were not always compensated for in one week of adaptation. Compensation was more pervasive for/s/and took the form of preservation of the general orientation of the air channel in spite of the palatal asymmetries present.

scholarly journals Numerical Investigation of Lift Force Increase in a Hovercraft by Changing the Geometrical Parameters of Flow Transfer Part and Air Channel

2020 ◽  
Vol 15 (30) ◽  
pp. 81-92
Author(s):  
Hossein Sadeghi ◽  
Mehrshad Yassari ◽  
Mohsen Pourfallah ◽  
Mohammad Molla Alipour ◽  
Ahmad Ali Rabienataj Darzi ◽  
...  
Keyword(s):  
Numerical Investigation ◽  
Lift Force ◽  
Geometrical Parameters ◽  
Force Increase ◽  
Air Channel ◽  
Flow Transfer

scholarly journals A heat transfer analysis from a porous plate with transpiration cooling

2019 ◽  
Vol 23 (5 Part B) ◽  
pp. 3025-3034 ◽  
Author(s):  
Mustafa Kilic
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Porous Plate ◽  
Particle Diameter ◽  
Heat Transfer Analysis ◽  
Transpiration Cooling ◽  
Cooling Efficiency ◽  
Cooling Effectiveness ◽  
Cooling Effects ◽  
Air Channel

Present study is focused on improving heat transfer from a porous plate by cooling of air with transpiration cooling. Effects of Reynolds number of the air channel flow and particle diameter on cooling effectiveness of porous plate and efficiency of system were investigated experimentally. It was observed that increasing Reynolds number of 15.2% causes a decrease of 6.9% on cooling efficiency of the system and a decrease of 8.6% on cooling effectiveness of porous plate. Decreasing particle diameter causes a significant decrease on surface temperature and an increase on cooling effectiveness of porous plate. Difference of cooling effectiveness of porous plate from dp = 40-200 ?m is 12%. Verification of this study was also shown by comparing experimental results of this study with literature.

The Effect of Injection and Suction on the Interfacial Mass Transport Resistance in a Proton Exchange Membrane Fuel Cell Air Channel

2014 ◽  
Author(s):  
Mustafa Koz ◽  
Satish G. Kandlikar
Keyword(s):  
Proton Exchange Membrane ◽  
Numerical Study ◽  
Gas Diffusion ◽  
Proton Exchange ◽  
Channel Cross Section ◽  
Flow Through ◽  
Air Channel ◽  
Air Channels ◽  
Exchange Membrane

Proton exchange membrane fuel cells are efficient and environmentally friendly electrochemical engines. The present work focuses on air channels that bring the oxidant air into the cell. Characterization of the oxygen concentration drop from the channel to the gas diffusion layer (GDL)-channel interface is a need in the modeling community. This concentration drop is expressed with the non-dimensional Sherwood number (Sh). At the aforementioned interface, the air can have a non-zero velocity normal to the interface: injection of air to the channel and suction of air from the channel. A water droplet in the channel can constrict the channel cross section and lead to a flow through the GDL. In this numerical study, a rectangular air channel, GDL, and a stationary droplet on the GDL-channel interface are simulated to investigate the Sh under droplet induced injection/suction conditions. The simulations are conducted with a commercially available software package, COMSOL Multiphysics.

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