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Title: Buoyant plume calculations

Abstract

Smoke from raging fires produced in the aftermath of a major nuclear exchange has been predicted to cause large decreases in surface temperatures. However, the extent of the decrease and even the sign of the temperature change, depend on how the smoke is distributed with altitude. We present a model capable of evaluating the initial distribution of lofted smoke above a massive fire. Calculations are shown for a two-dimensional slab version of the model and a full three-dimensional version. The model has been evaluated by simulating smoke heights for the Hamburg firestorm of 1943 and a smaller scale oil fire which occurred in Long Beach in 1958. Our plume heights for these fires are compared to those predicted by the classical Morton-Taylor-Turner theory for weakly buoyant plumes. We consider the effect of the added buoyancy caused by condensation of water-laden ground level air being carried to high altitude with the convection column as well as the effects of background wind on the calculated smoke plume heights for several fire intensities. We find that the rise height of the plume depends on the assumed background atmospheric conditions as well as the fire intensity. Little smoke is injected into the stratosphere unlessmore » the fire is unusually intense, or atmospheric conditions are more unstable than we have assumed. For intense fires significant amounts of water vapor are condensed raising the possibility of early scavenging of smoke particles by precipitation. 26 references, 11 figures.« less

Authors:
; ;
Publication Date:
Research Org.:
Lawrence Livermore National Lab., CA (USA)
OSTI Identifier:
6139588
Report Number(s):
UCRL-90915; CONF-850136-5
ON: DE85007255
DOE Contract Number:
W-7405-ENG-48
Resource Type:
Conference
Resource Relation:
Conference: 23. AIAA aerospace sciences meeting, Reno, NV, USA, 14 Jan 1985
Country of Publication:
United States
Language:
English
Subject:
45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEFENSE; 54 ENVIRONMENTAL SCIENCES; NUCLEAR EXPLOSIONS; ENVIRONMENTAL IMPACTS; PLUMES; DIFFUSION; CLIMATES; FIRES; HUMIDITY; MATHEMATICAL MODELS; SMOKES; WIND; AEROSOLS; COLLOIDS; DISPERSIONS; EXPLOSIONS; RESIDUES; SOLS; 450202* - Explosions & Explosives- Nuclear- Weaponry- (-1989); 500300 - Environment, Atmospheric- Radioactive Materials Monitoring & Transport- (-1989)

Citation Formats

Penner, J.E., Haselman, L.C., and Edwards, L.L.. Buoyant plume calculations. United States: N. p., 1985. Web.
Penner, J.E., Haselman, L.C., & Edwards, L.L.. Buoyant plume calculations. United States.
Penner, J.E., Haselman, L.C., and Edwards, L.L.. Tue . "Buoyant plume calculations". United States. doi:. https://www.osti.gov/servlets/purl/6139588.
@article{osti_6139588,
title = {Buoyant plume calculations},
author = {Penner, J.E. and Haselman, L.C. and Edwards, L.L.},
abstractNote = {Smoke from raging fires produced in the aftermath of a major nuclear exchange has been predicted to cause large decreases in surface temperatures. However, the extent of the decrease and even the sign of the temperature change, depend on how the smoke is distributed with altitude. We present a model capable of evaluating the initial distribution of lofted smoke above a massive fire. Calculations are shown for a two-dimensional slab version of the model and a full three-dimensional version. The model has been evaluated by simulating smoke heights for the Hamburg firestorm of 1943 and a smaller scale oil fire which occurred in Long Beach in 1958. Our plume heights for these fires are compared to those predicted by the classical Morton-Taylor-Turner theory for weakly buoyant plumes. We consider the effect of the added buoyancy caused by condensation of water-laden ground level air being carried to high altitude with the convection column as well as the effects of background wind on the calculated smoke plume heights for several fire intensities. We find that the rise height of the plume depends on the assumed background atmospheric conditions as well as the fire intensity. Little smoke is injected into the stratosphere unless the fire is unusually intense, or atmospheric conditions are more unstable than we have assumed. For intense fires significant amounts of water vapor are condensed raising the possibility of early scavenging of smoke particles by precipitation. 26 references, 11 figures.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Jan 01 00:00:00 EST 1985},
month = {Tue Jan 01 00:00:00 EST 1985}
}

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  • Dispersion modeling of buoyant exhausts in the vicinity of building clusters, such as from boilers, incinerators, and diesel generators, is often conducted using wind tunnel modeling. The receptors of interest are usually air intakes within the building clusters. Exact wind tunnel modeling of buoyant plume rise requires stack exhaust Froude number scaling between model simulations and the full scale, along with undistorted exit densities and ratios of exit velocity to approach wind speed. The Froude number requirements constrains the air speed in the tunnel to be lower than 0.5 m/s for typical geometric scale reductions. Such low air speeds canmore » make the air flow around the buildings Reynolds number dependent, an undesirable result. Distortions of exhaust density ratios and of exit diameters have been suggested in the past to maintain higher tunnel speeds. Davidson has presented an analytical plume rise equation which combines the 1/3 and 2/3 exponent laws for momentum-dominated and buoyancy-dominated plume rise. The analytical model was reported to compare well with water flume data. Davidson also recommends that the equation can be used to predict the errors in modeled plume rise when various wind tunnel modeling schemes are used to avoid the Froude number modeling requirement. This paper extends the work of Davidson by comparing the analytical equation to several wind tunnel and field plume rise databases. The analytical equation is then used to examine wind tunnel modeling schemes for two types of buoyant exhausts commonly modeled near buildings: emergency diesel generators and boilers.« less
  • This paper presents the development of integrate interactive graphics for the UDKHDEN and PDS mixing zone models. Iterative graphics were integrated in such a manner as to provide the user with a high degree of freedom in displaying the results graphically on the screen. The graphics created show plume shape, trajectory and concentration contours in multicolored bands. The UDKHDEN program calculates the characteristics of a line of equally spaced buoyant discharges into flowing stratified ambient water. The PDS program considers a buoyant discharge at the surface into ambient waters that has a uniform velocity and temperature distribution. Both programs aremore » used extensively to predict dilution in environmental discharges.« less
  • Equations for the steady-state rise of a buoyant plume are derived directiy from the conservation laws for mass, momentam and energy. Top-hat profiles are used and it is assumed that there is no horizontal pressure gradient across the plume's boundary. In the resulting equations there are four unspecified quantities: the drag and heat transfer coefficients, the entrainment velocity and heat production. Results are shown for the (isentropic) case when all these quantities are zero as well as for cases with various combination of these quantities different from zero and using simple relaxation models. In this way some insight is gainedmore » into their separate eftects on the plume's propenties. Results of a simple model to account for a mean wind are also demonstrated. The need for more field data is obvious. (auth)« less
  • The Emergency Dose Calculation Model for Three Mile Island Unit 1 (TMI-1) was recently revised to take into account the guidance of NUREG/CR-3354: Potentially Buoyant Releases at Boiling and Pressurized Water Reactors. The guidance provided was applied to the modeling of radioactive steam releases from the main steam relief valves and atmospheric dump valves at TMI-1. This paper presents an overview of the modeling of the plume rise and its impact on off-site doses.