Internet-Based Channel Orientation for Domesticated Services Firm: Some Drivers and Consequences

2019 ◽  
pp. 90-103
Author(s):  
Michael Adu Kwarteng ◽  
Abdul Bashiru Jibril ◽  
Fortune Nwaiwu ◽  
Michal Pilik ◽  
Maged Ali
Keyword(s):  
Channel Orientation

Local Heat Transfer in Rotating Smooth and Ribbed Two-Pass Square Channels With Three Channel Orientations

1996 ◽  
Vol 118 (3) ◽  
pp. 578-584 ◽  
Author(s):  
S. Dutta ◽  
J.-C. Han
Keyword(s):  
Heat Transfer ◽  
Rotation Number ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Transfer Coefficients ◽  
Channel Changes ◽  
Square Channel ◽  
Heat Transfer Coefficients ◽  
Experimental Heat ◽  
Channel Orientation

This paper presents experimental heat transfer results in a two-pass square channel with smooth and ribbed surfaces. The ribs are placed in a staggered half-V fashion with the rotation orthogonal to the channel axis. The channel orientation varies with respect to the rotation plane. A change in the channel orientation about the rotating frame causes a change in the secondary flow structure and associated flow and turbulence distribution. Consequently, the heat transfer coefficient from the individual surfaces of the two-pass square channel changes. The effects of rotation number on local Nusselt number ratio distributions are presented. Heat transfer coefficients with ribbed surfaces show different characteristics in rotation number dependency from those with smooth surfaces. Results show that staggered half-V ribs mostly have higher heat transfer coefficients than those with 90 and 60 deg continuous ribs.

scholarly journals Effects of Rotation at Different Channel Orientations on the Flow Field inside a Trailing Edge Internal Cooling Channel

2013 ◽  
Vol 2013 ◽  
pp. 1-19 ◽  
Author(s):  
Matteo Pascotto ◽  
Alessandro Armellini ◽  
Luca Casarsa ◽  
Claudio Mucignat ◽  
Pietro Giannattasio
Keyword(s):  
Flow Field ◽  
Working Conditions ◽  
Turbine Blades ◽  
Internal Cooling ◽  
Cooling Channel ◽  
Trailing Edge ◽  
Gas Turbine Blades ◽  
Sst Turbulence Model ◽  
Channel Orientation ◽  
Effects Of Rotation

The flow field inside a cooling channel for the trailing edge of gas turbine blades has been numerically investigated with the aim to highlight the effects of channel rotation and orientation. A commercial 3D RANS solver including a SST turbulence model has been used to compute the isothermal steady air flow inside both static and rotating passages. Simulations were performed at a Reynolds number equal to 20000, a rotation number (Ro) of 0, 0.23, and 0.46, and channel orientations ofγ=0∘, 22.5°, and 45°, extending previous results towards new engine-like working conditions. The numerical results have been carefully validated against experimental data obtained by the same authors for conditionsγ=0∘and Ro = 0, 0.23. Rotation effects are shown to alter significantly the flow field inside both inlet and trailing edge regions. These effects are attenuated by an increase of the channel orientation fromγ=0∘to 45°.

Bubble Behavior at an Uneven Wall

2016 ◽  
Author(s):  
H. Shmueli ◽  
G. Ziskind ◽  
R. Letan
Keyword(s):  
Bubble Growth ◽  
Three Dimensional ◽  
Grid Method ◽  
Numerical Code ◽  
Interface Tracking ◽  
Bubble Behavior ◽  
Three Dimensional Model ◽  
Surface Geometry ◽  
Initial State ◽  
Channel Orientation

The present study deals with single bubble growth on an uneven wall. A model problem is defined and solved using a three-dimensional numerical simulation. The wall has the shape of a triangular cavity and feature vortices. The equations solved in the present study are based on macro region modelling of the bubble alone and describe its growth from the initial state to detachment from the surface and consequent motion. The model includes a simultaneous solution of conservation equations for the liquid and gaseous phases, in conjunction with three-dimensional interface tracking. The latter is achieved using the level-set method. The numerical modeling includes the multi-grid method. The complete three-dimensional model is discretized using an original in-house numerical code realized in MATLAB. Different cases of bubble growth on the triangular cavity walls are investigated. The main conclusion from the calculations is that the bubble shape and its growth rate strongly depend on its location and on the channel orientation. New features, not possible for flat walls and special for this case, are revealed and discussed. It is demonstrated that under certain conditions, the bubble is obstructed by the surface geometry. It is also shown how a growing bubble affects the flow field inside a cavity, interacting with the vortex structure.

Effect of Channel Orientation of Local Heat (Mass) Transfer Distributions in a Rotating Two-Pass Square Channel With Smooth Walls

1998 ◽  
Vol 120 (3) ◽  
pp. 624-632 ◽  
Author(s):  
C. W. Park ◽  
S. C. Lau
Keyword(s):  
Mass Transfer ◽  
Coriolis Force ◽  
Heat Mass Transfer ◽  
Control Volume ◽  
Local Heat ◽  
Local Mass ◽  
Square Channel ◽  
Sharp Turn ◽  
Local Mass Transfer ◽  
Channel Orientation

Naphthalene sublimation experiments have been conducted to study the effects of channel orientation, rotational Coriolis force, and a sharp turn, on the local heat (mass) transfer distributions in a two-pass square channel with a sharp turn and smooth walls, rotating about a perpendicular axis. The test channel was oriented so that the direction of rotation was perpendicular to or at a 45 deg angle to the leading and trailing walls. The Reynolds number was kept at 5,500 and the rotation number ranged up to 0.24. For the radial outward flow in the first straight pass of the diagonally oriented channel, rotation-induced Coriolis force caused large monotonic spanwise variations of the local mass transfer on both the leading and trailing walls, with the largest mass transfer along the outer edges of both walls. Rotation did not lower the spanwise average mass transfer on the leading wall and did not increase that on the trailing wall in the diagonally oriented channel as much as in the normally oriented channel. The combined effect of the channel orientation, rotation, and the sharp turn caused large variations of the local mass transfer distributions on the walls at the sharp turn and immediately downstream of the sharp turn. The velocity fields that were obtained with a finite difference control-volume-based computer program helped explain how rotation and channel orientation affected the local mass transfer distributions in the rotating two-pass channel.

Effects of Orientation on Critical Heat Flux From Chip Arrays During Flow Boiling

1992 ◽  
Vol 114 (3) ◽  
pp. 290-299 ◽  
Author(s):  
C. O. Gersey ◽  
I. Mudawar
Keyword(s):  
Heat Flux ◽  
Critical Heat Flux ◽  
Single Phase ◽  
Cooling System ◽  
Flow Boiling ◽  
Flow Channel ◽  
Two Phase ◽  
Channel Orientation ◽  
Two Phase Cooling ◽  
Layer Development

Boiling experiments were performed with FC-72 on a series of nine in-line simulated microelectronic chips in a flow channel to ascertain the effects of channel orientation on critical heat flux (CHF). The simulated chips, measuring 10 mm × 10 mm, were flush-mounted to one wall of a 20 mm × 5 mm flow channel. The channel was rotated in increments of 45 degrees through 360 degrees such that the chips were subjected to coolant in upflow, downflow, or horizontal flow with the chips on the top or bottom walls of the channel with respect to gravity. Flow velocity was varied between 13 and 400 cm/s for subcoolings of 3, 14, 25, and 36°C and an inlet pressure of 1.36 bar. While changes in angle of orientation produced insignificant variations in the single-phase heat transfer coefficient, these changes had considerable effects on the boiling pattern in the flow channel and on CHF for velocities below 200 cm/s,’ with some chips reaching CHF at fluxes as low as 18 percent of those corresponding to vertical upflow. Increased subcooling was found to slightly dampen this adverse effect of orientation. The highest CHF values were measured with near vertical upflow and/or upward-facing chips, while the lowest values were measured with near vertical downflow and/or downward-facing chips. These variations in CHF were attributed to differences in flow boiling regime and vapor layer development on the surfaces of the chips between the different orientations. The results of the present study reveal that, while some flexibility is available in the packaging of multi-chip modules in a two-phase cooling system, some orientations should always be avoided.

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