Fundamental Analysis of Impeller Power Consumption

Fundamental momentum and energy analyzes can be used to verily the relationships obtained by dimensional analysis. The theory might be of more general interest thus a brief outline is presented in this section. 

In this analysis the moment of a force with respect to an axis, namely, torque, is important. Although the linear momentum equation can be used to solve problems involving torques, it is generally more convenient to apply the angular moment equation for this purpose. By forming the moment of the linear momentum and the resultant force associated with each particle of fluid with respect to a point in an inertial coordinate system, a moment of moment equation that relates torque and angular momentum flow can be obtained. 

Our starting point is the familiar Newton s second law for a single rigid particle  

The torque exerted by the force F about a flxed point is [79]  

By convention the angular momentum vector h is defined as the vector product of the radius vector to the particle and the linear momentum  

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