Theoretical prediction model of transient performance for a mixed flow pump under fast start-up conditions

Abstract

There always appears unsteady characteristics during start-up periods of pumps, which can lead to instability of the entire system. However, the lack of a method for quickly and accurately predicting pump start-up performance makes it difficult to analyze the performance of the overall system during the period. To this end, a theoretical model to predict pump transient performance under fast start-up conditions is established in the present study. The theoretical prediction model for pump steady performance is built based on loss modeling firstly. Then, the balance between pump transient head and pipeline system is considered to determine transient pump performance. A time stepping algorithm is proposed to solve transient pump performance during start-up periods. The established theoretical model and corresponding time stepping algorithm are applied to a mixed-flow pump under fast start-up conditions with various acceleration time. The predicted evolution of pump head shows good agreement with experimental measurements, and average relative errors are within 10% for both steady and transient conditions. In addition, the theoretical model is applied to analyze the transient performance of oscillating curves and impact head. The mechanism for predicted oscillating results, as well as the relation between peak impact head and the acceleration of rotation speed are revealed.

Hydraulic loss characteristics of closed-loop piping system during start-up process of mixed-flow pump

“…The SST k - ω turbulence model was used for steady-state numerical simulation as it can predict the flow field with adverse pressure gradients (Liu et al ., 2023). The transport equations for k and ω are given by:…”

Optimization of geometric parameters of hydraulic turbine runner in turbine mode based on ISMA and BPNN

“…The structure of ECNN and HCNN is shown in Figure 2. The calculation methods of RMSE and R are shown in Equations ( 6) and (7). The modeling effects of ECNN and HCNN are shown in Figure 3.…”

“…1 The forms of hydraulic turbines include reverse pump type, pump type, and water turbine type, [2][3][4] among which the commonly used one is reverse pump type with a simple structure. [5][6][7] Given the advantages of pump reversal as a hydraulic turbine, many scholars have conducted relevant research on it. Carravetta 8 and Mohammad 9 conducted a study on the use of reverse pumps for residual pressure recovery in water supply networks.…”

“…As an efficient energy recovery device, the hydraulic turbine is widely used in seawater desalination, oil hydrocracking, residue hydrodesulfurization, urban water network decompression, and other industries 1 . The forms of hydraulic turbines include reverse pump type, pump type, and water turbine type, 2–4 among which the commonly used one is reverse pump type with a simple structure 5–7 . Given the advantages of pump reversal as a hydraulic turbine, many scholars have conducted relevant research on it.…”

Prediction of centrifugal pump performance parameters based on a multilayer hybrid model

“…In the past few decades, numerous mechanism models have been proposed by simplifying the mass, momentum and energy conservation laws based on the researchers' experience [6,7] have been proposed by researchers based on energy conservation and mass conservation laws and their experience. Experience accumulation can reduce prediction time and cost.…”