ZBOT-DP

Status

Pending Funding

Key Science Questions to be Investigated

• How is liquid atomization/disintegration different in microgravity?
• How is transport of droplet different in microgravity?
• What is the effect of droplet evaporation on tank pressure? Is it affected by non-condensable gas?
• How is droplet-wall and droplet-interface interaction modified in microgravity?
• What is the effect of flash vaporization on the walls?
• Is the Leidenfrost effect strong enough to propel droplets away from the wall in microgravity?
• How is this film formation and transport different in microgravity?

Implication of ZBOT-DP Findings for Propellant Tank Design

• Advantages of a change to Droplet Phase Change pressure control design from jet mixing:
  • Depressurizes the tank using evaporation therefore not susceptible to non-condensable gas effects
  • Will not lead to cavitation at the LAD screen as observed in first ZBOT investigation
  • Pressure control is independent of ullage location that changes continuously in microgravity
• Disadvantages of Droplet Phase Change design:
  • Is ZBO using Droplet Phase Change feasible in microgravity? – it has never been tested in microgravity
  • More complicated than jet mixing

What are the impacts of microgravity and NC gases on droplet phase change & transport in a sealed tank.