Influence of Tip Clearance on Unsteady Flow in Automobile Engine Pump

Taking a two-stage variable-pitch axial fan as the research object, five schemes, including a single counter-flow rib layout grooved tip, are numerically simulated using the fluent software. The results indicate that, compared with the original blade tip, the total pressure rise and efficiency of the four proposed schemes have been improved to various degrees, with Scheme 4 (groove tip with double counterflow ribs) displaying the best performances. The total pressure and efficiency are increased by 113.44 Pa and 0.955%, respectively. The blade tip leakage flow is reduced to varying degrees under different schemes, according to the following order: Scheme 1, Scheme 2, Scheme 4, and Scheme 3 leading to a reduction of 7.44%, 6.46%, 5.36%, and 4.35%, respectively. Steady results are used as the initial condition for the ensuing strength check and modal analysis.

Section: Introductionmentioning

confidence: 99%

Influence of a Winglet Combined with a Groove Tip on the Performances of a Variable-Pitch Axial Flow Fan

Zhou¹,

Zhou²,

Ye³

2022

“…Based on the passive control principle, the effect of different pump structures on the pressure fluctuation and noise has been extensively explored. Cheng et al and Dai et al [17,18], discussed the different structures on pressure fluctuation at various locations in pumps. Wang et al [19] analyzed the influence of blade number on flow-induced noise at pump outlet.…”

Section: Introductionmentioning

confidence: 99%

“…Additionally, the noise optimization design was mainly realized by comparing the noise at pump outlet with different geometry parameters of pump structures, then revealing the optimal geometry parameter. However, the flow instability degree at various locations is different in pumps [17,18], the flow-induced noise at pump outlet may not be sufficient to evaluate the overall noise level in the noise optimization design process. Besides, the centrifugal pumps need to operate under various operating conditions to meet different demands, and the flow-induced noise changes accordingly.…”

Section: Introductionmentioning

confidence: 99%

Investigation on the Changing Characteristics of Flow-Induced Noise in a Centrifugal Pump

Li¹,

Sun²,

Wang³

et al. 2021

Centrifugal pumps are widely used in engineering for a variety of applications. A known drawback of these devices is the high-level noise generated during operations, which can affect their stability and adversely influence the entire working environment. By combining the Powell vortex sound theory, numerical simulations and experimental measurements, this research explores the trends of variation and the corresponding underlying mechanisms for the flow-induced noise at various locations and under different operating conditions. It is shown that the total sound source intensity (TSSI) and total sound pressure level (TSPL) in the impeller, in the region between the inlet to the outlet and along the circumferential extension of the volute, are much higher than those at pump inlet and outlet. Additionally, under various rotational speeds with the design flow rate (Condition 1), the TSSI and TSPL at pump inlet and outlet are higher than those obtained with the opening of the valve kept unchanged (Condition 2); vice versa when these two parameters are evaluated at various locations in the impeller and the volute under the Condition 2, they exceed the equivalent values obtained for the other Condition 1.

“…In addition, the relative position between the flow passage components will also affect the flow characteristics of the fluid which is passing through it, causing pressure fluctuation. Dai et al [17] conducted research and found that under different tip clearances, the pressure fluctuations in the flow field showed significant periodic changes. The pressure gradient of the engine pump will also change periodically as the impeller rotates.…”

Section: Introductionmentioning

confidence: 99%

Influence of the Axial Position of the Guide Vane on the Fluctuations of Pressure in a Nuclear Pump

Cheng¹,

Jiang²,

Li³

et al. 2020

The influence of the axial mount position of the guide vane on the pressure fluctuation in a nuclear pump (AP1000) is investigated. The characteristics of the three-dimensional flow inside the nuclear pump are analyzed by means of numerical simulation. Results indicate that when the axial relative distance between the guide vane and the pumping chamber is reduced, in conditions of "small flow," the efficiency of the pump increases, the pressure inside the pumping chamber decreases, while the losses related to the guide vane grow. Under large flow conditions, as the efficiency of the pump decreases, the losses for the guide vane and the pumping chamber increase. The pressure fluctuation in the annular pumping chamber is basically determined by the rotation frequency and the blade passing frequency. The magnitude of these fluctuations is affected by the guide vane axial position. In particular, the smallest possible amplitude is obtained when the outlet central plane of the guide vane coincides with the outlet axis of the pumping chamber.