Novel Heat Sink Design Utilizing Ionic Wind for Efficient Passive Thermal Management of Grid-Scale Power Routers

2015 ◽  
Vol 7 (3) ◽  
Author(s):  
Noris Gallandat ◽  
J. Rhett Mayor
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Numerical Model ◽  
Heat Transfer Enhancement ◽  
Thermal Management ◽  
Heat Sink ◽  
Ionic Wind ◽  
Transfer Enhancement ◽  
Enhancement Method ◽  
Heat Sink Design

This paper presents a numerical model assessing the potential of ionic wind as a heat transfer enhancement method for the cooling of grid distribution assets. Distribution scale power routers (13–37 kV, 1–10 MW) have stringent requirements regarding lifetime and reliability, so that any cooling technique involving moving parts such as fans or pumps are not viable. A new heat sink design combining corona electrodes with bonded fin arrays is presented. The model of the suggested design is solved numerically. It is predicted that applying a voltage of 5 kV on the corona electrodes could increase the heat removed by a factor of five as compared to natural convection.

Ionic Wind Heat Transfer Enhancement in Vertical Rectangular Channels: Experimental Study and Model Validation

2017 ◽  
Vol 9 (2) ◽  
Author(s):  
Noris Gallandat ◽  
Federico Bonetto ◽  
J. Rhett Mayor
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Natural Convection ◽  
Heat Transfer Enhancement ◽  
Heat Sink ◽  
High Reliability ◽  
Ionic Wind ◽  
Transfer Enhancement ◽  
Wind Generator ◽  
Rectangular Channels

This paper presents the results of an experimental study of ionic wind heat transfer enhancement in internal rectangular channels. Ionic wind is a potential technique to enhance natural convection cooling noise-free and without using moving part and thus ensuring a high reliability and a long lifetime. The goal of the present study is twofold: first, the multiphysics numerical model of ionic wind developed in previous work is validated experimentally. Second, the potential of the heat sink concept combining a fin array with an ionic wind generator is demonstrated by building a technology demonstrator. The heat sink presented in this work dissipates 240 W on a baseplate geometry of 200 × 263 mm. It is shown that the baseplate temperature can be reduced from 100 °C under natural convection to 81 °C when the ionic wind generator is turned on.

Effects of Insulated and Isothermal Baffles on Pseudosteady-State Natural Convection Inside Spherical Containers

2010 ◽  
Vol 132 (6) ◽  
Author(s):  
Yuping Duan ◽  
S. F. Hosseinizadeh ◽  
J. M. Khodadadi
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Heat Transfer Enhancement ◽  
Numerical Procedure ◽  
Boussinesq Approximation ◽  
Transfer Enhancement ◽  
Nusselt Numbers ◽  
Extended Surface ◽  
Parametric Studies ◽  
Thermal Layer

The effects of insulated and isothermal thin baffles on pseudosteady-state natural convection within spherical containers were studied computationally. The computations are based on an iterative, finite-volume numerical procedure using primitive dependent variables. Natural convection effect is modeled via the Boussinesq approximation. Parametric studies were performed for a Prandtl number of 0.7. For Rayleigh numbers of 104, 105, 106, and 107, baffles with three lengths positioned at five different locations were investigated (120 cases). The fluid that is heated adjacent to the sphere rises replacing the colder fluid, which sinks downward through the stratified stable thermal layer. For high Ra number cases, the hot fluid at the bottom of the sphere is also observed to rise along the symmetry axis and encounter the sinking colder fluid, thus causing oscillations in the temperature and flow fields. Due to flow obstruction (blockage or confinement) effect of baffles and also because of the extra heating afforded by the isothermal baffle, multi-cell recirculating vortices are observed. This additional heat is directly linked to creation of another recirculating vortex next to the baffle. In effect, hot fluid is directed into the center of the sphere disrupting thermal stratified layers. For the majority of the baffles investigated, the Nusselt numbers were generally lower than the reference cases with no baffle. The extent of heat transfer modification depends on Ra, length, and location of the extended surface. With an insulated baffle, the lowest amount of absorbed heat corresponds to a baffle positioned horizontally. Placing a baffle near the top of the sphere for high Ra number cases can lead to heat transfer enhancement that is linked to disturbance of the thermal boundary layer. With isothermal baffles, heat transfer enhancement is achieved for a baffle placed near the bottom of the sphere due to interaction of the counterclockwise rotating vortex and the stratified layer. For some high Ra cases, strong fluctuations of the flow and thermal fields indicating departure from the pseudosteady-state were observed.

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