A microgravity experiment of the on-orbit fluid transfer technique using swirl flow

Area of Science:

• Spacecraft engineering
• Fluid dynamics
• Cryogenics

Background:

• Cryogenic fluid transfer is crucial for long-duration space missions.
• Current methods require complex mechanisms to manage tank pressure and minimize vaporization losses.

Purpose of the Study:

• To develop a novel, simplified cryogenic fluid transfer technique for microgravity.
• To investigate the effectiveness of swirl flow combined with spray cooling for gas-liquid separation and vapor condensation.

Main Methods:

• Experimental investigation of swirl flow under microgravity conditions.
• Analysis of factors including inlet points, fluid velocity, fluid type, and boiling conditions.
• Utilizing Froude number for determining swirl flow conditions.

Main Results:

• The proposed swirl flow technique effectively achieves gas-liquid separation and vapor condensation without specialized mixers.
• Incoming liquid cools the tank wall, significantly reducing vaporization.
• The technique is effective for cryogenic fluids with low surface tension and good wettability.

Conclusions:

• The novel swirl flow and spray cooling method offers a flexible and low-cost solution for cryogenic fluid transfer in space.
• This technique can be readily applied to real systems due to its reliance on the dimensionless Froude number.
• The fundamental principles for cryogenic fluid transfer using swirl flow in microgravity have been established.