Flow performance analysis on shutoff condition in centrifugal pump based on CFD simulation

Abstract

CFD simulations on flow field of centrifugal pumps at shutoff are generally performed by means of minor-flow assumption, which are different from real operating condi tions and hard to well predict pump performances at shu toff. In this paper, therefore, the zero-flow boundary con dition was taken to proceed to a numerical simulation of unsteady flow for the type IS 125 centrifugal pump. The pump performances were predicted and verified by the pump performance test. The numerical result shows that there are different distributions of flow field and hydraulic load in the impeller channels, leading to the serious fluc tuations of pumps performance. At the shutoff, the volute tongue suffers from the most serious flow impact among all operating conditions. It is also found that the channels of the impeller near the upstream of volute are water discharging, but the channels of the impeller near the downstream of volute are water-inhaling. These results indicate that impeller channels have different flow ability while rotating at different positions. The numerical me thod and results can be benefit and referred for the opera tion and the design of centrifugal pumps.

Study on head characteristics of low-charge conditions of vertical centrifugal pump with medium-low specific speed

“…the model test of pump and the scale up from model pump(2) The analysis value is close to experimental value to prototype pump.near the vicinity of design point. The deviation are larger The results of numerical simulation and model test show:at the low-charge and high-charge conditions, however, (1) The head near the zero-charge condition (Qrn = 1 lis) the overall trend of the curves is the same; the efficiencyof scaling up from the model pump to the prototype pump flow characteristic curve is similar to the head-flow char-IS 239.99 m, higher than the maxImum head, namely acteristic curve.…”

“…It shows that the numerical simula tion results by using SST k-OJ were turbulence model the closest to the model test result. (2) Through the CFO simulation analysis and model tests of the model pump, the result of the model pump tests shows that the head of the prototype pump scaled from the model test result was higher than the head value from numerical analysis. The head value scaled from the model test result was 239.99 m at the zero-charge condi tion, and higher than the maximum head, namely 233.2 m, and has sufficient margin; the actual head of the prototype pump at the zero-charge condition was 260 m, signifi cantly higher than the scaled value from the model test.…”

“…Recent years, many scholars began CFD analysis at the zero charge and low-charge conditions. The CFD numerical simulation and PIV research on internal flow field of the centrifugal pump with specific speed 65 at the zero-charge condition were conducted by Huangping [1]; the perform ance at the zero-charge and low-charge conditions based on the IS 125 centrifugal pump as research objects were predicted by Huangsi [2]; through the analysis of the cen trifugal pump performance curve, the influence of impel ler parameters to impact on the hump was put forwarded by Li xiangzhou [3], which was important for the design of the pump; numerical simulations at the low-charge conditions to the low specific speed centrifugal pump were carried on by Zhubo [4]. Currently, the improvement of the head of the centrifugal pump at the low-charge con ditions was mainly based on correction.…”

Experimental evaluation of temperature rise in centrifugal pumps at partial flow rates

“…For 0.25Q n , their CFD results predicted different types of back flows in the impeller region, including steady leading edge separations, rotating vortex in the impeller wake region, and back flow on the impeller pressure side. Many other researchers presented identical flow patterns for off-design conditions using CFD, LDV and PIV methods and revealed the main portion of the recirculation zones and separated flows on energy wasting of the absorbed power for undesired flow pattern [9][10][11][12][13][14]. Recently, hydrodynamic instabilities and cavitating patterns of the fluid flow below design point have been discussed employing vibration analysis and pressure fluctuation measurements [15][16][17][18][19].…”

Characteristic Curve Prediction of a Commercial Centrifugal Pump Operating as a Turbine Through Numerical Simulations

“…They are used in different sectors: water desalination, mining industry, petrochemical plants, and distribution of drinking water [20]. The characteristic curve of centrifugal pumps has been validated in literature, finding errors of 12%, 5-10% and 4%, respect to efficiency [21][22][23]. In addition, the fluid dynamic behavior with pressure and velocity contours has been validated.…”