Inlet swirl decay of non-Newtonian fluid in laminar flows through tubes

Use of swirling velocity at the inlet has been a classical way to enhance the transport properties of flow within pipes. Owing to the laminar nature of flow of fluids in small tubes, enhancing transport within such tubes is very important for applications involving fluid mixing or heat transfer. Non-Newtonian fluids have varied applications in small pipes ranging from heat pipes to micro heat exchangers. To enhance the transport characteristics, we adopt the method of including swirling of fluid at the inlet of the pipe. Considering this, we investigate the effect of the power-law index of the fluid on the decay of the inlet swirl. We find that the length through which swirl decays to 1% of its value at inlet is strongly dependent on the power-law index value. A correlation for the decay length as a function of Reynolds number and power-law index is developed.