This application's long-term objective is the optimization of exhaust hoods used in industrial ventilation, maximizing the capture ability and minimizing the air flow through the hood. Such an approach will reduce worker exposure as well as the cost of operating the exhaust system. To accomplish this goal, a theoretical and experimental research plan is proposed. The theoretical approach will utilize a combination of conformal mapping and superimposition techniques to obtain closed form solutions for several hood geometries. Once a solution has been obtained, the results will be tested experimentally. In the preliminary investigation we carried out, excellent results were obtained. Following similar techniques, initially simple geometries will be studied. Thereafter, solutions for more complex geometries will be sought. If the theoretical solutions can be verified, the solutions for the governing equations can be used to design generalized shapes and seek optimum geometries in systems which include interference to flow by processes. The next step will be the verification of the capture capabilities of the hoods simulating practical applications. Obstructions in front of the hoods will be introduced as well as crossdrafts. The efficiency will be determined with a tracer gas (SF6 or Freon) which will be introduced in front of the hood. By knowing the amount of gas released and the amount captured by the hood, the collection efficiency can be calculated and thereby safety factors for design can be determined. This information will be used to develop a computer aided design scheme for optimum hood design.
