Fluid Dynamics in Space Vehicles

Southwest Research Institute (SwRI) is internationally recognized for its expertise in liquid dynamics in space vehicles. The Institute has been heavily involved in research and development efforts for fluid-thermal systems in space vehicles since the advent of the U.S. space program in the late 1950s. In 1966, SwRI published for NASA The Dynamic Behavior of Liquids in Moving Containers (NASA SP-106), which quickly became known in the aerospace industry as the "handbook" of sloshing.

With the initiation of the Space Station Freedom, Strategic Defense Initiative (SDI), and National Aerospace Plane (NASP) programs and the emergence of a commercial satellite industry, a renewed interest in fluid-thermal systems for both power requirements and environment control emerged. SwRI contributed to all of these programs and has aided many satellite manufacturers in the design, analysis, and testing of propellant management systems.

The Institute has studied both the sloshing of liquids in rocket tanks and the characteristics of slosh baffles. SwRI is a pioneer in the study of low-gravity sloshing and one of the earliest investigators of propellant management devices that control satellite and shuttle on-orbit spatial orientation.

In addition to these long-term projects, SwRI is developing fundamental liquid dynamics experiments for the Cryogenic On-orbit Liquid Depot Storage, Acquisition, and Transfer (COLD-SAT) satellite, a spinning tank experiment for the In-Space Technology Experimental Program (IN-STEP), unique compressors for Space Station Freedom, and early fluid/thermal system concepts for a lunar base and an outpost on Mars.

With more than 30 years of experience and a broad technical base in liquid sloshing, propellant management, power and propulsion, environmental control, computational fluid dynamics, and space hardware development, SwRI will continue to play a prominent role in solving new and challenging problems of the 1990s and beyond.

Liquid Sloshing

  • Fuel sloshing in rocket tanks
  • Rotary slosh dynamics
  • Nonlinear dynamics in elastic containers
  • Liquid behavior in randomly excited containers
  • Low-G sloshing
  • Fuel sloshing in fuel feed ducts
  • Spin-stabilized satellite tanks
  • Missile tanks sloshing
  • Hydrazine satellite tank sloshing

A one-fifth-scale model of a Centaur rocket liquid hydrogen propellant tank is prepared for a liquid dynamics test in an Institute laboratory.

A laboratory slosh test is performed on a full-scale model of the propellant tanks used in the Telemetering and Data Relay Satellite. A flexible membrane contains and expels the propellant in flight.

Space Propellant Management

  • Cryogenic fluid management experiment
  • COLD-SAT flight experiment
  • Liquid rocket propellant feedline dynamics
  • Liquid jet impingement on screens
  • Bellows flow-induced vibrations
  • Liquid acquisition devices (LAD)
  • Liquid dynamics in rocket fuel tanks
  • Propellant management devices (PMD)
  • Slush hydrogen dynamics
  • Liquid motion in spinning tank experiment (LME)

Long space flights requiring large fuel tanks need accurate fuel mass monitoring methods. SwRI is developing a technique that gauges the total fuel mass by measuring the tank's response to pressure pulses. Shown is a laboratory-scale model of the system's pulser motor and linkage.

Power and Propulsion

  • On-orbit compressor development
  • Auxiliary power unit adiabatic compression and overspeed
  • Shockwave interaction in cascades
  • Fuel nozzle research
  • Combustion physics
  • Gas turbine performance
  • Turbine inlet flow studies
  • High-temperature fuels

On-orbit compressor technology was developed by SwRI to support Space Station Freedom. This prototype unit, seen on cover, transports waste gas from station experimental modules to storage and disposal vessels.

Environmental Control and Life Support Systems (ECLSS)

  • Space station ECLSS leak detection
  • Orbiter ECLSS life extension
  • Space station ECLSS long-life design
  • Lunar base ECLSS study
  • Innovative ECLSS development

Liquids moving in spinning spacecraft tanks can cause instabilities in the spacecraft attitude control system or even complete loss of control, resulting in mission failure or expensive repair operations, such as shown at left. Many of the liquid motions occurring in space cannot be investigated in laboratory experiments. In a 1995 space shuttle experiment, SwRI will fly this set of scale-model spacecraft tanks (right) to measure, in an actual space environment, the liquid forces that cause spacecraft instabilities.

Computational Fluid Dynamics

  • Advanced launch facility flow field
  • Multiphase/multi-component separation
  • Mixing of reactive flows
  • Buoyant flows/heat transfer
  • Low-gravity fluid motion
  • Fluid transient analysis
  • Direct numerical and large eddy simulation code development
  • Turbulence modeling

Space Flight Experiments

  • Research on orbital plasma electrodynamics (ROPE)
  • Suprathermal plasmas in cometary environment (SPICE)
  • Thermal ion drift experiment (TIDE)
  • Plasma interaction monitoring system (PIMS)
  • Liquid motion in spinning tanks experiment (LME)

SwRI developed the isochronous time-of-flight mass spectrograph, a high-resolution energy/mass analyzer designed for in situ investigations of space plasmas.

Space Flight Instruments

  • High-altitude plasma instrument (HAPI)
  • Low-altitude plasma instrument (LAPI)
  • Fast ion mass spectrometer (FIMS)
  • Soft particle spectrometer (SPS)
  • Particle environment monitor (PEM)

The Institute is systems contractor and integrator for the Particle Environment Monitor (PEM), a package of several instruments developed for the NASA Upper Atmosphere Research Satellite (UARS).

Space Flight Control Computers (SC-1-5)

  • Force torque sensor (FTS)
  • High-resolution Doppler interferometer (HRDI) experiment-control electronics
  • Low-power atmosphere compensation experiment (LACE)
  • Relay mirror experiment (RME)
  • Space experiments with particle accelerators (SEPAC)
  • Wide-angle "Michelson" Doppler imaging interferometer (WAMDII)
  • Wave in space plasma (WISP)

SwRI's Angle Resolving Energy Analyzer measures energy and angular distribution of electrons in space.

This brochure was published in July 1993. For more information about fluid dynamics in space vehicles, contact Steve Green, Vice President, Phone (210) 522-2384, Fax (210) 522- 5122, Mechanical Engineering Division, Southwest Research Institute, P.O. Drawer 28510, San Antonio, Texas 78228-0510.

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