Thanks for the comments Dave (myv65).
Am aware of the effects of viscosity on jet impingement efficiency. Was talking primarily here about a fairly narrow range of impingement scenarios though where we aren't moving too far away from the edges of the jet (r = 1.0-2.0d from middle). Viscosity in this region under the primary influence of the incoming jet is of reduced overall impact when the jet nozzle is brought down to about 1.5-2.5d distance due to the pressure of the jet stripping away the boundary layer fairly effectively in that small region.
What we're left with is the thermal conductivity of the liquid then being of prime importance. As I noted, bringing the flow rates up above 4LPM or so effectively nullifies any loss due to the fluid's lower capacitance (as you also pointed out).
What I was seeing was that within that fairly tightly defined scenario, a thermal conductivity of 4x of water (which CuSO4.5H2O has) places it better than water for heat removal even if it had a viscosity of as much a 10x higher than water. Above 10x higher viscosity and water wins again.
From what I've been able to find out, it seems that CSP has a viscosity of around 12x that of water, so basically we're back at square one - water is still better.
Boli, yes. that's the stuff. It will only form crystals if the amount of water in it gets below the saturation point of the substance, where it will dry out into a crystallised form.
Lowering the concentration is of no real use. Yes, that lowers the viscosity, but it also lowers the thermal conductivity at about the same rate, so that effectively kicks out any gain from even doing that...
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