Impact of blade number on performance, loss and flow characteristics of one mixed flow turbine

Ketata, Ahmed; Driss, Zied; Abid, Mohamed Salah

doi:10.1016/j.energy.2020.117914

Cited by 15 publications

(14 citation statements)

References 10 publications

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“…Thiyagaraj 21 finds that an appropriate number of blades can improve the power coefficient of turbine. Ahmed 22 points out that passage and incidence losses decrease with the increase in blade numbers, which improving the swallowing capacity and efficiency. Ibnu 23 finds out that the water discharge decreased with the increase in blade numbers.…”

Section: Introductionmentioning

confidence: 99%

Influence of blade number on performance of multistage hydraulic turbine in turbine mode

Zhang

et al. 2022

Energy Science & Engineering

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Compared with the traditional reverse multistage pump as hydraulic turbine, hydraulic turbine in turbine mode (T‐type turbine) with low specific speed has higher single‐stage energy head, which can effectively reduce stages and increase the stability when it is used to recycle high residual pressure liquid. Blade number of runner is an important design parameter, which has great influence on the performance of T‐type hydraulic turbine and need to be further studied. Therefore, two‐stage T‐type turbine models with different blade numbers are established through numerical simulation. Then, the accuracy of numerical simulation is verified by test. Finally, the performance and pressure fluctuating characteristics of turbine with different blade numbers are obtained. The results show that: (a) Taking same blade numbers in both stages (traditional design method), the turbine efficiency can be higher with the blade number of primary runner and secondary runner are 14, but resulting the superposition of pulsation in secondary runner; (b) Taking different blade numbers in both stages, respectively, the superposition of pulsation can be effectively avoided, which also leads to the increase in efficiency, and up to 81.169%; (c) The method of using different number of blades in different stages can replace the traditional design method and effectively improve the hydraulic performance of T‐type hydraulic turbine.

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Section: Introductionmentioning

confidence: 99%

Influence of blade number on performance of multistage hydraulic turbine in turbine mode

Zhang

et al. 2022

Energy Science & Engineering

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“…Turbocharging consists of a partial exhaust gas recovery to boost the engine intake, thereby allowing fuel savings and fewer pollutant emissions. The effectiveness of such boosting system significantly depends on the performance of the turbine, a key component of turbochargers as shown by several anterior research works (Menacer and Bouchetara, 2013, 2014; Ketata et al , 2020b). It has been recognized that the fixed geometry turbine (FGT) had different limitations such as the time lag and poor transient response toward low engine loads (Serrano et al , 2009b).…”

Section: Introductionmentioning

confidence: 99%

A methodology for loss and performance assessment of a variable geometry turbocharger turbine through a new meanline FORTRAN program

Ketata

Driss

2021

Self Cite

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PurposeVariable geometry turbine (VGT), a key component of modern internal combustion engines (ICE) turbochargers, is increasingly used for better efficiency and reduced exhaust gas emissions. The aim of this study is the development of a new meanline FORTRAN code for accurate performance and loss assessment of VGTs under a wider operating range. This code is a useful alternative tool for engineers for fast design of VGT systems where higher efficiency and minimum loss are being required.Design/methodology/approachThe proposed meanline code was applied to a variable geometry mixed flow turbine at different nozzle vane angles and under a wide range of rotational speed and the expansion ratio. The numerical methodology was validated through a comparison of the predicted performance to test data. The maps of the mass flow rate as well as the efficiency of the VGT system are discussed for different nozzle vane angles under a wide range of rotational speed. Based on the developed model, a breakdown loss analysis was carried out showing a significant effect of the nozzle vane angle on the loss distribution.FindingsResults indicated that the nozzle angle of 70° has led to the maximum efficiency compared to the other investigated nozzle vane angles ranging from 30° up to 80°. The results showed that the passage loss was significantly reduced as the nozzle vane angle increases from 30° up to 70°.Originality/valueThis paper outlines a new meanline approach for variable geometry turbocharger turbines. The developed code presents the novelty of including the effect of the vane radii variation, due to the pivoting mechanism of the nozzle ring. The developed code can be generalized to either radial or mixed flow turbines with or without a VGT system.

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“…Ketata et al. 34 found that an increase in the number of blades would reduce the loss in the flow passage and increase the flow capacity and efficiency of the impeller. However, up to now, there has been no relevant report on the effect of blade number on the stall interval of mixed-flow rotating machinery.…”

Section: Introductionmentioning

confidence: 99%

“…31,32 Zhong 33 believed that there was an optimal combination of the number of rotor and stator blades for the cascade consistency of the mixed flow pump, and the efficiency and head of the mixed flow pump could be improved if they are adjusted according to certain rules. Ketata et al 34 found that an increase in the number of blades would reduce the loss in the flow passage and increase the flow capacity and efficiency of the impeller. However, up to now, there has been no relevant report on the effect of blade number on the stall interval of mixed-flow rotating machinery.…”

Section: Introductionmentioning

confidence: 99%

Influence of different blade numbers on the performance of “saddle zone” in a mixed flow pump

Shi

et al. 2021

Proceedings of the Institution of Mechanical Engineers, Part A:

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In order to study the effect of different numbers of impeller blades on the performance of mixed-flow pump “saddle zone”, the external characteristic test and numerical simulation of mixed-flow pumps with three different impeller blade numbers were carried out. Based on high-precision numerical prediction, the internal flow field and tip leakage flow field of mixed flow pump under design conditions and stall conditions are investigated. By studying the vorticity transport in the stall flow field, the specific location of the high loss area inside the mixed flow pump impeller with different numbers of blades is located. The research results show that the increase in the number of impeller blades improve the pump head and efficiency under design conditions. Compared to the 4-blade impeller, the head and efficiency of the 5-blade impeller are increased by 5.4% and 21.9% respectively. However, the increase in the number of blades also leads to the widening of the “saddle area” of the mixed-flow pump, which leads to the early occurrence of stall and increases the instability of the mixed-flow pump. As the mixed-flow pump enters the stall condition, the inlet of the mixed-flow pump has a spiral swirl structure near the end wall for different blade numbers, but the depth and range of the swirling flow are different due to the change in the number of blades. At the same time, the change in the number of blades also makes the flow angle at 75% span change significantly, but the flow angle at 95% span is not much different because the tip leakage flow recirculates at the leading edge. Through the analysis of the vorticity transport results in the impeller with different numbers of blades, it is found that the reasons for the increase in the values of the vorticity transport in the stall condition are mainly impacted by the swirl flow at the impeller inlet, the tip leakage flow at the leading edge and the increased unsteady flow structures.

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Impact of blade number on performance, loss and flow characteristics of one mixed flow turbine

Cited by 15 publications

References 10 publications

Influence of blade number on performance of multistage hydraulic turbine in turbine mode

Influence of blade number on performance of multistage hydraulic turbine in turbine mode

A methodology for loss and performance assessment of a variable geometry turbocharger turbine through a new meanline FORTRAN program

Influence of different blade numbers on the performance of “saddle zone” in a mixed flow pump

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