Design Of Multistage Pump Research Articles

Numerical investigationof clocking effect of impellerson a multistage pump

Purpose The purpose of this paper is to investigate the clocking effect of impellers and the superposition between pump stages caused by clocking effect in a five-stage centrifugal pump. Then the best clocking scheme in terms of vibration is tried to be provided as well. Design/methodology/approach All curves of pressure fluctuation in different impeller stages can be divided into two groups for the difference of 1/16 T in time domain. The difference is mostly in vibration frequency and amplitude, little in pump head and efficiency. Findings All curves of pressure fluctuation in different impeller stages can be divided into two groups for the difference of 1/16 T in time domain. The difference is mostly in vibration frequency and amplitude, little in pump head and efficiency. Research limitations/implications This research involves eight different impeller clocking schemes. The results show that the clocking effect has little influence in pump head and efficiency, but the influence in pressure fluctuation is larger. Practical implications The paper provides guidance for the design of multistage pump for better vibration performance. Originality/value This research involves eight different impeller clocking schemes, the results show that the clocking effect has little influence in pump head and efficiency, but the influence in pressure fluctuation is larger. Then the best clocking scheme In terms of vibration is tried to be provided through analysis.

Effects of Inlet-Loss Coefficient on Dynamic Coefficients and Stability of Multistage Pump Annular Seal

In order to explore the influence of inlet-loss coefficient on dynamic coefficients and stability of finite-length annular seal, and then to provide theoretical basis for multistage pump rotor system vibration and stability, the bulk-flow model is taken into account to model the fluid control equations of clearance flow, and perturbation method is applied to calculate the first-order functions and dynamic coefficients. The calculated results are validated by comparing them with reference results, and the minimum and maximum error percentage are 1.4 and 5.6%, respectively. The dynamic coefficients change rule and stability of annular seal under the multifactor-coupled effects are researched in a detailed manner. The numerical results show that the inlet-loss coefficient plays an important role in dynamic coefficients of finite-length annular seal, especially for direct stiffness. All of the dynamic coefficients increase with the increase in inlet-loss coefficient, and the growth trends are the most distinct for large length–diameter ratio, small clearance or high rotating speed. Moreover, reducing the inlet-loss coefficient can improve the stability of annular seal. The research results and conclusions can provide references for the structure design of multistage pump and optimal design of rotor system.

Flow characteristics of Roots pumps with multistage designs by CFD investigation

This study conducts a fluid analysis of multistage designs for a Roots pump, a type of positive displacement pump applied in blower and vacuum pumps. After a rotor profile is generated based on a mathematical model of a rotor, a three-dimensional numerical approach is developed using computational fluid dynamics (CFD) and applied to investigate the effect of multistage pump design on flow characteristics. The effects of serial versus parallel designs on fluid are illustrated using a two-lobed rotor. The fluid analysis, which pays particular attention to favorable stages, shows that in both serial and parallel connection designs, having more than three stages improves flow characteristics but to a relatively small degree because of increased leakage. It identifies the three-stage design as offering the greatest economy for pumping performance enhancement. A similar analysis is then performed on a three-lobed rotor design using the same three-stage design. A comparison of the flow characteristics of the two- versus three-lobed rotors based on serial versus parallel design and identical chamber volume identifies specific variations in flow rate, pressure, and pulsation.

Multi-Stage Centrifugal Pump Impeller Hydraulic Model Modification and Performance Analysis

The multi-stage centrifugal pump run instability at the original design point, and the running operating point deviated far from the design point during the run. In order to better meet the multi-stage centrifugal pump operational requirements, through hydraulic model modification, changing the multi-stage pump design point, while the performance curve before and after the modification can be interchangeable in the flow of 150m3/h~320m3/h. The original program used 3 blades impeller. Taking into account the matching problem with pressurized water chamber, modification plan used 5 blades impeller. Analysis on the internal flow field before and after the modification was made. Through comparison the internal and external characteristics of the two plans, the analysis found that in the double volute pressurized water chamber, the flow field symmetry of 5 blades is better than the 3 blades’. The flow field symmetry can be well balanced radial force, and help to improve the instability phenomenon in operation.

Development of an electroosmotic pump for high performance actuation

Electroosmotic pumps have been used in a variety of applications, typically for systems that require very low flow rates and/or pressures. The objective of this work was to develop an electroosmotic pump capable of driving a high mechanical advantage actuator that could generate large block stresses and large strains, requiring actuation pressures in excess of 0.1 MPa with flow rates on the order of 0.1 mL/s. Experiments were performed using inorganic silica and alumina membranes with different pore size. Data were obtained over a range of solution ionic strength, with results compared to model calculations developed from numerical solution of the Navier–Stokes and Poisson–Boltzmann equations. These results were used to construct a multi-stage electroosmotic pump capable of providing the desired flow rates and pressures. This multi-stage pump design was sufficiently flexible to allow adaptation to a variety of applications.

Multiobjective Optimization of Rocket Engine Pumps Using Evolutionary Algorithm

A design optimization method for turbopumps of cryogenic rocket engines has been developed. Multiobjective evolutionary algorithm is used for multiobjective pump design optimizations. Performances of design candidates areevaluated by using the meanline pump flow-modeling method based on the Euler turbine equation coupled with empirical correlations for rotor efficiency. To demonstrate feasibility of the present approach, single-stage centrifugal pump and multistage pump design optimizations are performed. The number of pump performance evaluations necessary to obtain a reasonable pareto-optimal set for the conceptual rocket engine pump design will be investigated using the single-stage centrifugal pump design optimization. In both design optimizations the present method obtains hundreds of reasonable and uniformly distributed pareto-optimal solutions that include some designs outperforming the original design in total head while reducing input power by 1%. Detailed observation of the design results also reveals some important design criteria for turbopumps in cryogenic rocket engines. These results demonstrate the feasibility of the evolutionary algorithm-based multiobjective design optimization method in this field.