Compact Thermal Energy Storage Unit for Next Generation Reusable Launch Vehicles

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Compact Thermal Energy Storage Unit for Next
Generation Reusable Launch Vehicles

• Shavonne Ford and G. D. Wesson

Department of Chemical Engineering Florida AM
University/Florida State University
Presented at College of Engineering
Tallahassee, FL August 3, 2001
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Outline

• Motivation
• Background
• Problem Statement
• Future Work

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Motivation

• NASA Space shuttle
• Cooling system for the hydraulic fluid
• Ascending Descending Flight
• Time restriction
• Weight restriction
• Current system
• Water spray boiler system 210ºF
• Overheating causes the shuttle to lose
  maneuvering capabilities
• New system requires a lower temperature
• Requires a turn around service

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• Thermal heat storage systems
• Heat of reaction
• Latent heat
• More compact
• Constant temperature operation
• Heat exchanger integrated
• Optimize heat transfer area by using fins
• Reduces charging/discharging cycles
• Sensible heat

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Thermal Energy Equation

• Assumptions
• Constant pressure
• Constant density
• Neglect work by viscous forces
• Fluid at rest
• Heat transfer due to conduction

Rate of Heat added by conduction
Rate Of accumulation
Rate of work done by pressure forces
Rate of work done by viscous dissipation
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• Fouriers Law of Heat Conduction
• Unsteady Heat Conduction Equation

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Unsteady Heat Conduction Equation

• Part I Problem with single phase
• Part II Problem including phase change
  (Stefan Problem)

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Problem Statement

• Investigate the heat transfer process around a
  finned tube
• Finned tube enclosed by and external cylinder

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• Cylindrical Coordinate system
• 2 D system
• Thermal conductivity depends on position

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Simulation

• Numerically solved using Matlab
• Finite difference method explicit form
• Show surface plot w/label
• Talk about initial condition
• high temp to lower

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Future Work - Stefan Problem

• Investigate the solidification process around a
  finned tube
• Mode of heat transfer conduction only
• 3-D system
• Heat Capacity depends on Temperature
• Thermal conductivity depends on position and
  temperature

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• More than one phase
• Moving interface
• Enthalpy method
• No need to track the interface
• Valid for entire domain
• Solid, liquid and interface
• Easy to introduce the mushy region
• Numerically solve using Matlab
• Finite difference method and the enthalpy method
• Comparison with literature values

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• Thermal conductivity depends on temperature