Wyniki wyszukiwania - BazTech

1

Impact of the Volute Basic Circle Diameter of Sewage Pump on Pressure Pulsation

Li W., Shi W., Jiang X., Jiang T., Chen B.

Przegląd Elektrotechniczny

|

2013

|

R. 89, nr 3b

232--235

EN

The unsteady flow field in the channel sewage pump with three different basic circle diameters of volutes were numerically simulated based on the Fluent commercial software, using the standard k-ε turbulence model, the SIMPLE algorithm, and the sliding mesh technique. By setting pressure measurement points, the pressure pulsation in different positions can be obtained. The impact of the basic circle diameter of volute on the internal pressure pulsation characteristics of a sewage pump was analyzed based on frequency domain and time domain graphs. The results show that the smaller the basic circle diameter of volute is, the more turbulent the pressure pulsation is. The Coefficient of pressure pulsation amplitude reaches the maximum value with small gaps in the volute and impeller clearance. The closer the monitoring point to the cutwater, the greater the amplitude of pressure pulsation. In a flow channel of volute, the pressure fluctuation presents cyclical changes, and a small gap flow reaches the strongest unsteady characteristics. Pressure pulsation cycle is associated with the number of impeller blades and a period of three peaks is the blade passing frequency. The dominant frequency of pressure pulsation is 73.5Hz, which is the threefold frequency of rotation frequency.

PL

W artykule przedstawiono wyniki i opis symulacji przepływu w pompie kanalizacyjnej z trzema różnymi średnicami sprężyn napędowych. W badaniach wykorzystano oprogramowanie Fluent, jeden ze standardowych modeli turbulencji (k-epsilon), algorytm SIMPLE oraz technikę siatki przesuwnej. W analizie skupiono się na przypadku wystąpienia zakłóceń przepływu w kanale. Dokonano analizy wyników i przedstawiono wnioski.

2

Effect of Exit Blade Angle, Viscosity and Roughness in Centrifugal Pumps Investigated by CFD Computation

Li W.

TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk

|

2011

|

Vol. 15, No 1

21-41

EN

It has long been known that the exit blade angle plays a very important role in the performance of a centrifugal pump handling water or viscous oil. The effect of exit blade angle on the performance and flow of centrifugal pumps is usually investigated experimentally. However, due to the high cost and limited data that can be obtained by experiment, currently there is a great need for this effect to be studied numerically by means of computational fluid dynamics (CFD). At present, extensive comparisons between experiment and simulation regarding the performance of viscous oil and flow in centrifugal pumps with different exit blade angles are not available. Hydraulic performance and flow details in the impeller and the volute of a centrifugal pump with an exit blade angle of 44o were investigated numerically with the CFD code Fluent, using water and viscous oil as the working fluid, respectively. The effect of exit blade angle was then elucidated by comparing the performance and flow with that of a pump with an exit blade angle of 20o. It was determined that the results for the performance and flow obtained by means of CFD were in qualitative agreement with the observations. The sudden-rising-head effect is dependent on roughness and viscosity. The unstable zone in the theoretical head curve of the impeller at a low flow rate was attributed to the strong reaction of the volute to the flow in the vicinity of the impeller exit. The flow in the impeller with a large exit blade angle was subject to separation near the blade pressure side, however, a large exit blade angle helped improve the pump performance of viscous oil.

3

Numerical investigation of flow in mixed-flow pump with volute

Sedlar M.

TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk

|

2001

|

Vol. 5, No 4

595-602

EN

The work considers the modelling of flow in a complete mixed-flow pump with volute, including tip leakage flows, using both quasi-steady and true transient models of rotor/stator interaction. The CFX-TASCflow CFD package from AEA Technology is applied to calculate flows for a wide range of flow rates from about 0.2 to 1.4 Q/sub 0pt/. Fairly detailed flow structures have been predicted based on the flow rates, especially impeller inlet recirculation and separation on the suction side of the blades for suboptimal rates of flow, as well as strong secondary flows and separation in the volute for off-design conditions. The rotor/stator interaction influence on flow phenomena both in the impeller and volute have been investigated with very interesting results, providing good insight into the dynamics of flow close to the volute tongue. Based on the computational results, pump performance curves (Q-H, Q- eta /sub h/ and Q-P, eta /sub h/ being the hydraulic efficiency) have been obtained. The data from this numerical investigation have been used to improve the inlet part of the impeller blades, especially close to the tip. The geometry modifications have resulted in reduced cavitation in the impeller as well as noise at suboptimal rates of flow.