Physical modeling of heavy plume dispersion

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1989

OSTI ID:6678869

Neff, D E

An LNG vapor plume at boiloff conditions is heavier than air. Although the plume will eventually become positively buoyant due to heat absorbed from the surroundings, much of the dispersion will occur while the plume density is greater than that of air. In laboratory tests, dispersion during the heavier-than-air phase was approximated by means of isothermal-model plumes produced by high-molecular-weight gases. These heavy gases were introduced into a wind tunnel via an area source mounted flush on the wind-tunnel floor. Concentration sensors downwind of this source were used to measure the structure of the different model plumes tested. Methods for scaling between model tests and field scale events are defined. The concentration scaling theory used by previous investigators was found to cause large errors and a new theory was developed. An extensive data base on the structure of different laboratory heavy plumes was obtained. These experiments included a large range of conditions for source gas specific gravity, gas flow rate and wind speed. Three different procedures were formulated whereby a single model test can be predictive of a larger class of field events. These enhanced scaling procedures are analyzed with respect to the measured laboratory data base to assist in specification of their capabilities and limitations. A useful empirical description of all the continuous plume tests was developed, and its applicability to field conditions discussed. Model tests on measured field scale LNG spills were performed to validate physical modeling capabilities. When the model tests reproduced the approach flow wind characteristics properly the plume concentration field was in good agreement with the field test results.

• Research Organization: Colorado State Univ., Fort Collins, CO (USA)
• OSTI ID: 6678869
• Country of Publication: United States
• Language: English

Related Subjects

03 NATURAL GAS
030800* -- Natural Gas-- Environmental Aspects
54 ENVIRONMENTAL SCIENCES
540120 -- Environment
Atmospheric-- Chemicals Monitoring & Transport-- (1990-)
AIR
BENCH-SCALE EXPERIMENTS
DENSITY
ENERGY SOURCES
ENVIRONMENTAL TRANSPORT
FLOW MODELS
FLOW RATE
FLUID FLOW
FLUIDS
FOSSIL FUELS
FUEL GAS
FUELS
GAS FLOW
GAS FUELS
GAS SPILLS
GASES
LIQUEFIED GASES
LIQUEFIED NATURAL GAS
MASS TRANSFER
MATHEMATICAL MODELS
MOLECULAR WEIGHT
MONITORING
NATURAL GAS
PHYSICAL PROPERTIES
PLUMES
TUNNELS
UNDERGROUND FACILITIES
VELOCITY
WIND
WIND TUNNELS