Heat Entrapment Effects Within Liquid Acquisition Devices

Duval, Walter M. B.; Chato, David J.; Doherty, Michael F.

doi:10.2514/6.2010-1298

Cited by 1 publication

(2 citation statements)

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“…The dynamics of the system for Ra = 1 to 10 8 has been considered for an aspect ratio of Ar = 1 (Ref. 3), and a short-time solution for Ra = 10 9 is presented for Ar = 3.24 (Ref. 3).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Transient Convection Due To Imposed Heat Flux: Application to Liquid Acquisition Devices

Duval

Chato

Doherty

2011

49th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition

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A model problem is considered that addresses the effect of heat load from an ambient laboratory environment on the temperature rise of liquid nitrogen inside an enclosure. This model has applications to liquid acquisition devices inside the cryogenic storage tanks used to transport vapor-free propellant to the main engine. We show that heat loads from Q = 0.001 to 10 W, with corresponding Rayleigh numbers from Ra = 10 9 to 10 13 , yield a range of unsteady convective states and temperature rise in the liquid. The results show that Q = 1 to 10 W (Ra = 10 12 to 10 13 ) yield temperature distributions along the enclosure height that are similar in trend to experimental measurements. Unsteady convection, which shows selfsimilarity in its planforms, is predicted for the range of heat-load conditions. The onset of convection occurs from a free-convection-dominated base flow that becomes unstable against convective instability generated at the bottom of the enclosure while the top of the enclosure is convectively stable. A number of modes are generated with small-scale thermals at the bottom of the enclosure in which the flow selforganizes into two symmetric modes prior to the onset of the propagation of the instability. These symmetric vertical modes transition to asymmetric modes that propagate as a traveling-wave-type motion of convective modes and are representative of the asymptotic convective state of the flow field. Intense vorticity production is created in the core of the flow field due to the fact that there is shear instability between the vertical and horizontal modes. For the higher Rayleigh numbers, 10 12 to 10 13 , there is a transition from a stationary to a nonstationary response time signal of the flow and temperature fields with a mean value that increases with time over various time bands and regions of the enclosure.

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“…The dynamics of the system for Ra = 1 to 10 8 has been considered for an aspect ratio of Ar = 1 (Ref. 3), and a short-time solution for Ra = 10 9 is presented for Ar = 3.24 (Ref. 3).…”

Section: Introductionmentioning

confidence: 99%

“…3), and a short-time solution for Ra = 10 9 is presented for Ar = 3.24 (Ref. 3). Herein, we consider the asymptotic dynamics for Ra = 10 9 and Ar = 3.24, and we extend the calculations to Ra = 10 13 for the highest heat-load condition.…”

Section: Introductionmentioning

confidence: 99%