US 4,671,805 AGranted

Method for airport fog precipitation

AssigneeEnergy Innovations, Inc.

InventorMeredith C. Gourdine

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Abstract

Atmospheric occurrences that decrease visibility, particularly fog, smoke, smog and the like, are cleared at sites such as airports by an array of EGD spray units emitting submicron size charged water droplets to attach to airborne particulates and electrostatically precipitate those to ground. Independent variables of the array and the EGD jets from the spray units are controlled to control the dependent variables characterizing the space-charge cloud thus developed. The methods and apparatus control the height to which clearing of the airborne particulates occurs to improve visibility and the time required for such clearing. Specific compact spray units are self-contained, can be radio operated, and are movable. Placement of the units for removal of radiation and advection fog with respect to airport runways include a square array of the spray units proximate the runway for radiation fog control and upwind location of arrays for advection fog precipitation. Specific characteristics of small, medium and large spray units suitable for use in the arrays are set forth.

Claims19

Dependent claims

A method of precipitating airborne particles of fog, haze, smog and the like in an unconfined portion of the atmosphere to ground including:

(a) providing an array of charged submicron water droplet nozzles having a mean spacing S between the nozzles of the array;
(b) selecting characteristics of a cloud of charged submicron droplets to be produced by the array including:
(1) a field strength E.sub.x (0) of the cloud at the ground;
(2) a height H of the cloud;
(3) a charge concentration of q.sub.a n.sub.a, wherein q.sub.a is the average charge of a submicron droplet and n.sub.a is the concentration of charged submicron droplets;
(4) a time constant .tau.;
providing the nozzle array with the average spacing S, average kinetic power P.sub.j of the jets, average current I.sub.j in the jet, mobility of emitted charged submicron droplets k.sub.a and mobility of the charged fog drops k.sub.b such that S, P.sub.j, I.sub.j k.sub.a and k.sub.b provide the selected values of E.sub.x (0), H, q.sub.a n.sub.a pursuant to the relationships:
E.sub.x (0).varies.S.sup.-2/3 P.sub.j.sup.1/3 k.sub.a.sup.-1/3,
H.varies.S.sup.2/3 P.sub.j.sup.2/3 I.sub.j.sup.-1 k.sub.a.sup.1/3,
q.sub.a n.sub.a .varies.S.sup.-4/3 P.sub.j.sup.-1/3 I.sub.j k.sub.a.sup.-2/3,
.tau..varies.S.sup.4/3 P.sub.j.sup.1/3 I.sub.j.sup.-1 K.sub.a.sup.-1/3 (k.sub.b /k.sub.a).sup.-1,
and emitting charged submicron water droplets from the nozzles, the water droplets having the above-recited characteristics, whereby clearing of the airborne particles occurs to substantially the height H by attachment of the emitted submicron droplets to the airborne particles and precipitation of the thus charged airborne particles to the ground.

9 more elements

Dependencies are inferred from the claim text.