Numerical modeling of flow in a recuperation turbine in order to verify its performance parameters, including efficiency

Kód výsledku v IS VaVaI

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Výsledek na webu

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DOI - Digital Object Identifier

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Jazyk výsledku

angličtina

Název v původním jazyce

Numerical modeling of flow in a recuperation turbine in order to verify its performance parameters, including efficiency

Popis výsledku v původním jazyce

The purpose of the project is to investigate the flow in a centrifugal pump when it works as a turbine (PAT), with special interest in the prediction of performance curves and efficiency. The pump studied is one stage pump, with single axial suction and a vaneless spiral volute casing. The impeller design with low number of highly curved long blades is accommodated for waste water pumping with large solids. The results obtained with numerical modelling of the PAT performance under various operating condition are following conclusions: -The investigated recuperation pump is equipped with special impeller with long passages and curved blades which may lead to high hydraulic losses - In the numerical results, huge regions with detached flow with vortices can be observed in the impeller channels, which may be a consequence of the impact of the inflow angle derived by the volute tongue. - Due to the guidance of the flow within the runner curved passages, excessive post-rotation at the runner outlet and higher levels of residual dynamic pressure (linked to the tangential component) can be observed. This may contribute to the losses and reduction of the actual work available for power transfer to the shaft. - As the geometry of the pump operating as a turbine cannot be adjusted to variations in the flow rate, it can be expected that considerable deviations of the optimal flow may lead to a significant decrease in the performance and efficiency of the machine. - The PAT operating point will be given by the intersection between the turbine characteristic curve and the system characteristic curve (which is not known). If the systems curve changes, i.e. lower flow-rare is required, the rotational speed increases. If the flow-rate demand increases, rotational speed decreases. The turbine operates in the rotational speed ranging from 400 to 900 revolutions per minute. Based on the discussion with the company representatives, following parameters were chosen for further testing

Název v anglickém jazyce

Numerical modeling of flow in a recuperation turbine in order to verify its performance parameters, including efficiency

Popis výsledku anglicky

The purpose of the project is to investigate the flow in a centrifugal pump when it works as a turbine (PAT), with special interest in the prediction of performance curves and efficiency. The pump studied is one stage pump, with single axial suction and a vaneless spiral volute casing. The impeller design with low number of highly curved long blades is accommodated for waste water pumping with large solids. The results obtained with numerical modelling of the PAT performance under various operating condition are following conclusions: -The investigated recuperation pump is equipped with special impeller with long passages and curved blades which may lead to high hydraulic losses - In the numerical results, huge regions with detached flow with vortices can be observed in the impeller channels, which may be a consequence of the impact of the inflow angle derived by the volute tongue. - Due to the guidance of the flow within the runner curved passages, excessive post-rotation at the runner outlet and higher levels of residual dynamic pressure (linked to the tangential component) can be observed. This may contribute to the losses and reduction of the actual work available for power transfer to the shaft. - As the geometry of the pump operating as a turbine cannot be adjusted to variations in the flow rate, it can be expected that considerable deviations of the optimal flow may lead to a significant decrease in the performance and efficiency of the machine. - The PAT operating point will be given by the intersection between the turbine characteristic curve and the system characteristic curve (which is not known). If the systems curve changes, i.e. lower flow-rare is required, the rotational speed increases. If the flow-rate demand increases, rotational speed decreases. The turbine operates in the rotational speed ranging from 400 to 900 revolutions per minute. Based on the discussion with the company representatives, following parameters were chosen for further testing

Druh

V_souhrn - Souhrnná výzkumná zpráva

CEP obor

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OECD FORD obor

20301 - Mechanical engineering

Projekt

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Návaznosti

N - Vyzkumna aktivita podporovana z neverejnych zdroju

Rok uplatnění

2021

Kód důvěrnosti údajů

C - Předmět řešení projektu podléhá obchodnímu tajemství (§ 504 Občanského zákoníku), ale název projektu, cíle projektu a u ukončeného nebo zastaveného projektu zhodnocení výsledku řešení projektu (údaje P03, P04, P15, P19, P29, PN8) dodané do CEP, jsou upraveny tak, aby byly zveřejnitelné.

Počet stran výsledku

60

Místo vydání

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Název nakladatele resp. objednatele

BBA HRANICE,spol.s.r.o.

Verze

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