An Experimental Investigation into the Transit Performance of a Titanium-Water Loop Heat Pipe Subjected to a Steady-Periodic Acceleration Field (Postprint)
AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH PROPULSION DIRECTORATE
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The objective of this research is to experimentally investigate the transient operating characteristics of a titanium-water loop heat pipe subjected to a combined steady-state evaporator input heat rate and a steady-periodic acceleration field. For this experimental investigation, a steady-periodic acceleration field, in the form of a sine wave, was generated using a centrifuge table. Radial acceleration peak-to-peak values and frequency of the sine wave were defined prior to conducting each experimental run and ranged from 0.5g less than or equal to ar less than or equal to 10g, and 0.01Hz is less than or equal to f is less than or equal to 0.1Hz respectively. Evaporator input heat rate and condenser cold plate coolant temperature was varied 300W is less than or equal to Qin is less than or equal to 600W and 30 deg C is less than or equal to Tcp is less than or equal to 56 deg C respectively. In some cases acceleration driven forces complimented the thermodynamic forces improving LHP dynamical performance. However, the converse was also true in that transient acceleration driven forces also appeared to counter thermodynamic forces or excite natural frequencies of the LHP. This resulted in immediate total failure of the LHP to operate, delayed total failure, or in some cases, the LHP operated in a stable manner but in a degraded condition.