Active flow control of the vortex rope and pressure pulsations in a swirl generator
The vortex rope and pressure pulsations caused by a radial pressure gradient in the conical diffuser of a swirl generator is controlled using continuous slot jets with different momentum fluxes and angles injected from the runner crown. The swirl apparatus is designed to generate flows similar to th...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
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Taylor & Francis Group
2017-01-01
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| Series: | Engineering Applications of Computational Fluid Mechanics |
| Subjects: | |
| Online Access: | http://dx.doi.org/10.1080/19942060.2016.1235515 |
| _version_ | 1811254562860826624 |
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| author | Ardalan Javadi Håkan Nilsson |
| author_facet | Ardalan Javadi Håkan Nilsson |
| author_sort | Ardalan Javadi |
| collection | DOAJ |
| description | The vortex rope and pressure pulsations caused by a radial pressure gradient in the conical diffuser of a swirl generator is controlled using continuous slot jets with different momentum fluxes and angles injected from the runner crown. The swirl apparatus is designed to generate flows similar to those in the different operating conditions of a Francis turbine. The study is done with numerical modelling using the hybrid URANS-LES (Unsteady Reynolds-Averaged Navier–Stokes–Large Eddy Simulation) method with the rotor–stator interaction. The comprehensive studies of Javadi and Nilsson [Time-accurate numerical simulations of swirling flow with rotor–stator interaction. Flow, Turbulence and Combustion, Vol. 95, pp. 755–774], and Javadi, Bosioc, Nilsson, Muntean and Susan-Resiga [Experimental and numerical investigation of the precessing helical vortex in a conical diffuser, with rotor–stator interaction. ASME Journal of Fluids Engineering, doi:10.1115/1.4033416] are considered as the bench mark, and the capabilities of the technique is studied in the present work with the validated numerical results presented in those studies. The pressure pulsations caused by the pressure gradient generated by the swirl, present at off-design conditions, are cumbersome for hydropower structures. The investigation shows that the pressure pulsation, velocity fluctuations and the size of the vortex rope decrease when the jet is injected from the runner crown. The flow rate of the jet is less than 3% of the flow rate of the swirl generator. The momentum flux, angle of injection of the jet and the position of the slot are important factors for the effectiveness of the flow control technique. |
| first_indexed | 2024-04-12T17:09:22Z |
| format | Article |
| id | doaj.art-a8202a501db24b46ac1d318e19b322fd |
| institution | Directory Open Access Journal |
| issn | 1994-2060 1997-003X |
| language | English |
| last_indexed | 2024-04-12T17:09:22Z |
| publishDate | 2017-01-01 |
| publisher | Taylor & Francis Group |
| record_format | Article |
| series | Engineering Applications of Computational Fluid Mechanics |
| spelling | doaj.art-a8202a501db24b46ac1d318e19b322fd2022-12-22T03:23:51ZengTaylor & Francis GroupEngineering Applications of Computational Fluid Mechanics1994-20601997-003X2017-01-01111304110.1080/19942060.2016.12355151235515Active flow control of the vortex rope and pressure pulsations in a swirl generatorArdalan Javadi0Håkan Nilsson1Chalmers University of TechnologyChalmers University of TechnologyThe vortex rope and pressure pulsations caused by a radial pressure gradient in the conical diffuser of a swirl generator is controlled using continuous slot jets with different momentum fluxes and angles injected from the runner crown. The swirl apparatus is designed to generate flows similar to those in the different operating conditions of a Francis turbine. The study is done with numerical modelling using the hybrid URANS-LES (Unsteady Reynolds-Averaged Navier–Stokes–Large Eddy Simulation) method with the rotor–stator interaction. The comprehensive studies of Javadi and Nilsson [Time-accurate numerical simulations of swirling flow with rotor–stator interaction. Flow, Turbulence and Combustion, Vol. 95, pp. 755–774], and Javadi, Bosioc, Nilsson, Muntean and Susan-Resiga [Experimental and numerical investigation of the precessing helical vortex in a conical diffuser, with rotor–stator interaction. ASME Journal of Fluids Engineering, doi:10.1115/1.4033416] are considered as the bench mark, and the capabilities of the technique is studied in the present work with the validated numerical results presented in those studies. The pressure pulsations caused by the pressure gradient generated by the swirl, present at off-design conditions, are cumbersome for hydropower structures. The investigation shows that the pressure pulsation, velocity fluctuations and the size of the vortex rope decrease when the jet is injected from the runner crown. The flow rate of the jet is less than 3% of the flow rate of the swirl generator. The momentum flux, angle of injection of the jet and the position of the slot are important factors for the effectiveness of the flow control technique.http://dx.doi.org/10.1080/19942060.2016.1235515Flow controlvortex ropehybrid URANS-LESrotor–stator interaction |
| spellingShingle | Ardalan Javadi Håkan Nilsson Active flow control of the vortex rope and pressure pulsations in a swirl generator Engineering Applications of Computational Fluid Mechanics Flow control vortex rope hybrid URANS-LES rotor–stator interaction |
| title | Active flow control of the vortex rope and pressure pulsations in a swirl generator |
| title_full | Active flow control of the vortex rope and pressure pulsations in a swirl generator |
| title_fullStr | Active flow control of the vortex rope and pressure pulsations in a swirl generator |
| title_full_unstemmed | Active flow control of the vortex rope and pressure pulsations in a swirl generator |
| title_short | Active flow control of the vortex rope and pressure pulsations in a swirl generator |
| title_sort | active flow control of the vortex rope and pressure pulsations in a swirl generator |
| topic | Flow control vortex rope hybrid URANS-LES rotor–stator interaction |
| url | http://dx.doi.org/10.1080/19942060.2016.1235515 |
| work_keys_str_mv | AT ardalanjavadi activeflowcontrolofthevortexropeandpressurepulsationsinaswirlgenerator AT hakannilsson activeflowcontrolofthevortexropeandpressurepulsationsinaswirlgenerator |