An improved cavitation mixing and heating device employs an inlet directed toward the vertex of a conical or similar flow-directing element. The flow patterns of the fluid material to be mixed and heated are designed to preheat, spread, and create turbulent flow mixing of the fluid before it enters the cavitation zone, using heat generated in the cavitation zone that is conducted through the body of the cavitation rotor. The functions of the axially oriented inlet and flow directing element are assisted by a cantilever construction to alleviate stress on the bearings.