Author(s): Nikola Nikolov; Mariana Maradjieva
Linked Author(s): Mariana Maradjieva
Keywords: Rotary pump; Reversible operation; Protection; Back-pressure valvemembrane valve; Brake regime; Turbine regime; Revolution; Numerical method; Algorithm; Break-down disconnection; Similarity laws; Rated revolution; Transient process
Abstract: The reversible operation of rotary pumps results from the use of programmable membrane valves. These valves were used for the first time by the American company CLA-VAL, and were later produced also in Bulgaria. Some theoretical and experimental investigations were performed on the reversible operation of valves by taking into account the elasticity, rotary mass and the loss. A numerical model with a mounted membrane valve was developed and compared with the experimental data. The authors have studied membrane valves as means for protection because of their advantages as compared to back-pressure valves and other mechanical regulators. One advantage is that they have hydraulic closing permitting reversible revolutions smaller than the rated revolutions, and smaller pressure. In the present paper, an algorithm and numerical model are described in the case of reversible operation of rotary pumps. The final results show the value of the maximum reversible revolutions and the maximum pressure in the pump and the pipeline in the case of membrane valve protection. Moreover, a method is suggested for the development of four-quadrant characteristics of rotary pumps. The practical application of these characteristics in computer programs is possible by including correction factors depending on the dynamic equation of motion, similarity laws, experiments and spline functions. With a view to test the proposed algorithm, some experiments with analogue-digital equipment were carried out, and practical conclusions were drawn. The authors are looking for co-operation for further development of software, the algorithm and for Internet publicity.
Year: 2001