Response of porous beds to rapid gas pressurization
A two phase, one dimensional, Lagrange hydrodynamic program has been developed to compute the response of a porous bed to rapid gas pressurization. It has been used to investigate plug formation in porous beds, starting with different initial values for density (percent TMD), with different initial sized granulations (particle size), and with different values for material yield (flow) stress. The program is based upon a chain of finite element cells each of which represent the porous media with equations that assume the closure of a spherical pore. Gas flow is then treated with difference equations derived from the differential equations for adiabatic flow with friction in a circular duct. Since the cell definition includes discrete gas volume and gas flow area, the choice of calculational cell size is equivalent to the choice of a unique physical system, i.e., initial density and granulation. Calculational results are compared to data obtained on granulated rocket motor propellants in plastic pipe deflagration to detonation transition (DDT) experiments. These materials are very compliant. Experimental pressurization rates associated with detonation are shown to be of similar magnitude to the calculated pressurization rates that lead to the formation of a forward moving compaction plug. Calculational results are also compared with data from a DDT tube experiment performed on Winchester 231 reloading powder, a much less compliant material. A pressurization rate can be selected for which the calculated compaction front velocity agrees well with the experimentally observed luminous front velocity from the streak camera record. Also, the calculated displacement profiles are in reasonable agreement with experimental displacement profiles observed in x-ray photographs.
- Research Organization:
- Lawrence Livermore National Lab., CA (USA)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 6380164
- Report Number(s):
- UCID-19697; ON: DE83007309
- Country of Publication:
- United States
- Language:
- English
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420400 -- Engineering-- Heat Transfer & Fluid Flow
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450100* -- Military Technology
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CHEMICAL EXPLOSIVES
COMPACTING
COMPUTER CODES
D CODES
DETONATIONS
EXPLOSIVES
FLUID FLOW
FLUIDS
GASES
MATERIALS
PARTICLE SIZE
POROUS MATERIALS
PRESSURE DEPENDENCE
SIZE
SOLIDS
TWO-PHASE FLOW