Acceleration

As long as the wick’s capillary force is greater than the pressure drops and the acceleration loading, the heat pipe will perform properly under various acceleration loadings. However, extremely large adverse acceleration loadings may overwhelm the wick’s capillary capability, de-priming the wick or eventually causing the wick to dry out.

If the acceleration is for short durations, the wick structure will re-prime and the thermal transient may be within an allowable range. An alternative approach will be required if the transients are for longer durations.  If the axis and direction of acceleration are known the heat pipes can be configured such that acceleration helps return the condensed fluid “gravity aided”.  If the acceleration axis is unknown heat pipes can be arranged in pairs so that regardless of the acceleration vector one heat pipe will always be “gravity aided”; see Figure 1.  For further information, see Water Heat Pipe Parameters and Limitations.

Figure 4.  Dual heat pipes for high accelerations.  One set of the heat pipes always operates, since the acceleration returns the condensate to the evaporator.

Figure 4. Dual heat pipes for high accelerations. One set of the heat pipes always operates, since the acceleration returns the condensate to the evaporator.

 

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