Table 9 Experimental studies on cryogenic chill-down

Velat⁹²

Experimental investigation to collect detailed information on flow structure, flow properties, and heat transfer mechanisms associated with cryogenic chill-down.

1g

Liquid nitrogen

Visualizations of the entire chill-down process are documented among a range of mass fluxes. The existence and magnitude of circumferential and small axial temperature gradients in the transfer line during the various phases of chill-down is reported.

Hu et al.¹³⁴

Liquid nitrogen chill-down rates and flow patterns between upward flow and downward flow in a vertical pipe.

1g

Liquid nitrogen

Increasing mass flow rate, rewetting temperature, and quench front velocity increase while the critical heat flux decreases. The total chill-down time for upward flow is longer than for downward flow. Critical heat flux, heat transfer coefficient, and the quench front velocity are higher for upward flow.

Rame and Hartwig¹³⁵

Liquid hydrogen chill-down is experimentally studied for continuous and pulsed flow conditions

1g

Liquid nitrogen

The authors propose a connection between the non-monotonically decreasing temperature and the flow conditions, which increase the heat transfer coefficient.

Yuan et al.^93,96

Liquid nitrogen chill-down process under both normal gravity and microgravity conditions

0g, drop tower

Liquid nitrogen

The bottom wall heat flux is lower in 0g than in 1g. Wall temperature and inlet flow rate do depend on gravity.

Kawanami et al.¹⁰¹

Liquid nitrogen forced convective boiling for low mass velocity in terrestrial and microgravity conditions

1g, 0g

Liquid nitrogen

Heat transfer and quench front velocity is 20% higher in 0g. Gravity has no effect on the maximum heat flux, which increases exponentially with the quench front velocity.

Hartwig et al.¹³⁶

Chill-down in microgravity using pulse flow and low-thermally conductive coatings

Parabolic Flight

Liquid nitrogen

The tested combination of coatings and pulsating flow enhances significantly the performances of the chill-down: 75% reduction of mass consumption.

Sarae et al.⁴⁵

See Table 4.

Kinefuchi et al.⁴⁶

See Table 4.