Pressure Drop in Flexible Ducts

Abstract

In many ventilation system design requirements, a hood of one kind or another is required to be movable. This requirement calls for the use of flexible ducts. Although the availability of flexible ducts presents no problems, the designers have had to depend on rather scanty data in the estimation of pressure drop for air flow through flexible ducts. In general, data availability are limited to manufacturers' data sheets, and the information presented is not uniform. Experiments using two makes of flexible ducts and various sizes suggest a uniform method of pressure loss estimation for flexible ducts. The experimental results and the resulting equations suggest a direct and relatively simple estimation process.