Computational Modelling of the HyperVapotron Cooling Technique for Nuclear Fusion Applications PDF Download

Author: Joseph Milnes
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Languages : en
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Book Description
Efficient heat transfer technologies are essential for magnetically confined fusionreactors; this applies to both the current generation of experimental reactors as well asfuture power plants. A number of High Heat Flux devices have therefore been developedspecifically for this application. One of the most promising candidates is theHyperVapotron, a water cooled device which relies on internal fins and boiling heattransfer to maximise the heat transfer capability. Over the past 30 years, numerous variations of the HyperVapotron have been built andtested at fusion research centres around the globe resulting in devices that can nowsustain heat fluxes in the region of 20? 30MW/m2 in steady state. Unfortunately, therehave been few attempts to model or understand the internal heat transfer mechanismsresponsible for this exceptional performance with the result that design improvements aretraditionally sought experimentally which is both inefficient and costly. This thesis seeks to develop an engineering model of the HyperVapotron device usingcommercial Computational Fluid Dynamics software. To establish the most appropriatemodelling choices, in-depth studies were performed examining the turbulence models(within the Reynolds Averaged Navier Stokes framework), near wall methods, gridresolution and boiling submodels. Validation of the models is accomplished via comparison with experimental results aswell as high order Implicit Large Eddy Simulation methods. It is shown that single phasecavity flows and their related heat transfer characteristics (time-averaged) can beaccurately captured if the SST k-omega turbulence model is employed using a fine nearwallgrid throughout the cavity (e.g. y+