Experimental investigation of a progressively rotating flow of a viscous incompressible liquid in a cylindrical pipe

Conclusions

In summing up the data obtained by measuring the critical speed of the flow and the coefficients of the resistance to the flow and of heat emission it is possible to arrive at the conclusion that the experimental results fully confirm the theoretical relationships found in [1, 2]. Thus, for the calculation of the hydraulic resistance and the heat exchange in a turbulent progressively rotating liquid flow in a pipe the following formulas can be recommended:

$$\begin{gathered} \xi = \frac{{0.18}}{{\operatorname{Re} ^{0.25} \left( {1 - \frac{{2r_v }}{D}} \right)^{1.25} }}, \hfill \\ Nu = \frac{{0.12 \cdot Re^{0.75} }}{{\left( {1 - \frac{{2r_v }}{D}} \right)^{0.25} }}. \hfill \\ \end{gathered}$$

The first formula holds for any liquids. The second formula holds only for water. Its numerical coefficient should be changed for other liquids. Both formulas hold for the range of Re=w₀D/υ⩽8 · 10⁴.