Design Equation for Stirring Fluid by a Stream Pump in a Circulating Tank

Abstract

A circulating tank is a very useful theoretical scheme for many fluid-flow objects in several branches of engineering. The motion of the fluid in such objects can be induced in different ways. A stream pump provides an especially interesting possibility; however, the quantitative description of such devices shows some shortcomings. Such a device is analogous to a jet pump, thus has similar advantages (simplicity of construction, lack of movable elements, insensibility to pollutants) and disadvantages (low efficiency). On the one hand, from the technical viewpoint, one can make use of technical instructions presented in handbooks and offered by producers, and on the other hand by performing calculations using CFD tools. In this situation, it is self-evident that some intermediary method of design, i.e., formally simple, but physically convincing, would be welcome both by theoreticians and by engineers. Such a method is proposed in this paper and takes the form of an algebraic formula, combining the discharge of the stream pump and the discharge of the circulation induced by this stream. This expression, based on the balance between the power of the stream and the power of dissipation, has been experimentally verified with a positive result.