The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform
Hideaki Tamaki - One of the best experts on this subject based on the ideXlab platform.
-
Effect of Recirculation Device With Counter Swirl Vane on Performance of High Pressure Ratio Centrifugal Compressor
Journal of Turbomachinery, 2012Co-Authors: Hisashi Tamaki, Hideaki TamakiAbstract:Centrifugal compressors used for turbochargers need to achieve a wide operating range. The author has developed a high pressure ratio centrifugal compressor with pressure ratio 5.7 for a marine use turbocharger. In order to enhance operating range, two different types of recirculation devices were applied. One is a conventional recirculation device. The other is a new one. The conventional recirculation device consists of an upstream slot, bleed slot and the annular cavity which connects both slots. The new recirculation device has vanes installed in the cavity. These vanes were designed to provide recirculation flow with negative preswirl at the Impeller Inlet, a swirl counterwise to the Impeller rotational direction. The benefits of the application of both of the recirculation devices were ensured. The new device in particular, shifted surge line to a lower flow rate compared to the conventional device.
-
effect of recirculation device with counter swirl vane on performance of high pressure ratio centrifugal compressor
ASME 2011 Turbo Expo: Turbine Technical Conference and Exposition, 2011Co-Authors: Hideaki TamakiAbstract:Centrifugal compressors used for turbochargers need to achieve a wide operating range. The author has developed a high pressure ratio centrifugal compressor with pressure ratio 5.7 for a marine use turbocharger. In order to enhance operating range, two different types of recirculation devices were applied. One is a conventional recirculation device. The other is a new one. The conventional recirculation device consists of an upstream slot, bleed slot and the annular cavity which connects both slots. The new recirculation device has vanes installed in the cavity. These vanes were designed to provide recirculation flow with negative preswirl at the Impeller Inlet, a swirl counterwise to the Impeller rotational direction. The benefits of the application of both of the recirculation devices were ensured. The new device in particular, shifted surge line to a lower flow rate compared to the conventional device. This paper discusses how the new recirculation device affects the flow field in the above transonic centrifugal compressor by using steady 3-D calculations. Since the conventional recirculation device injects the flow with positive preswirl at the Impeller Inlet, the major difference between the conventional and new recirculation device is the direction of preswirl that the recirculation flow brings to the Impeller Inlet. This study focuses on two effects which preswirl of the recirculation flow will generate. (1) Additional work transfer from Impeller to fluid. (2) Increase or decrease of relative Mach number. Negative preswirl increases work transfer from the Impeller to fluid as the flow rate reduces. It increases negative slope on pressure ratio characteristics. Hence the recirculation flow with negative preswirl will contribute to stability of the compressor. Negative preswirl also increases the relative Mach number at the Impeller Inlet. It moves shock downstream compared to the conventional recirculation device. It leads to the suppression of the extension of blockage due to the interaction of shock with tip leakage flow.Copyright © 2011 by ASME
Hisashi Tamaki - One of the best experts on this subject based on the ideXlab platform.
-
Effect of Recirculation Device With Counter Swirl Vane on Performance of High Pressure Ratio Centrifugal Compressor
Journal of Turbomachinery, 2012Co-Authors: Hisashi Tamaki, Hideaki TamakiAbstract:Centrifugal compressors used for turbochargers need to achieve a wide operating range. The author has developed a high pressure ratio centrifugal compressor with pressure ratio 5.7 for a marine use turbocharger. In order to enhance operating range, two different types of recirculation devices were applied. One is a conventional recirculation device. The other is a new one. The conventional recirculation device consists of an upstream slot, bleed slot and the annular cavity which connects both slots. The new recirculation device has vanes installed in the cavity. These vanes were designed to provide recirculation flow with negative preswirl at the Impeller Inlet, a swirl counterwise to the Impeller rotational direction. The benefits of the application of both of the recirculation devices were ensured. The new device in particular, shifted surge line to a lower flow rate compared to the conventional device.
Tooru Suita - One of the best experts on this subject based on the ideXlab platform.
-
Detailed Flow Study of Mach Number 1.6 High Transonic Flow With a Shock Wave in a Pressure Ratio 11 Centrifugal Compressor Impeller
Journal of Turbomachinery, 2004Co-Authors: Hirotaka Higashimori, Kunio Sumida, Kiyoshi Hasagawa, Tooru SuitaAbstract:Requirements for aeronautical gas turbine engines for helicopters\ninclude small size, low weight, high output, and low fuel consumption.\nIn order to achieve these requirements, development work has been\ncarried out on high efficiency and high pressure ratio compressors.\nAs a result, we have developed a single stage centrifugal compressor\nwith a pressure ratio of 11 for a 1000 shp class gas turbine. The\ncentrifugal compressor is a high transonic compressor with an Inlet\nMach number of about 1.6. In high Inlet Mach number compressors,\nthe flow distortion due to the shock wave and the shock boundary\nlayer interaction must have a large effect on the flow in the inducer.\nIn order to ensure the reliability of aerodynamic design technology,\nthe actual supersonic flow phenomena with a shock wave must be ascertained\nusing measurement and CFD. This report presents the measured results\nof the high transonic flow at the Impeller Inlet using LDV and verification\nof CFD, with respect to the high transonic flow velocity distribution,\npressure distribution and shock boundary layer interaction at the\ninducer. The Impeller Inlet tangential velocity is about 460m/s and\nthe relative Mach number reaches about 1.6. Using an LDV, about 500m/s\nrelative velocity was measured preceding a steep deceleration of\nvelocity. The following steep deceleration of velocity at the middle\nof blade pitch clarified the cause as being the pressure rise of\na shock wave, through comparison with CFD as well as comparison with\nthe pressure distribution measured using a high frequency pressure\ntransducer. Furthermore, a reverse flow is measured in the vicinity\nof casing surface. It was clarified by comparison with CFD that the\nreverse flow is caused by the shock-boundary layer interaction. Generally\nCFD shows good agreement with the measured velocity distribution\nat the inducer and splitter Inlet, except in the vicinity of the\ncasing surface.
Hirotaka Higashimori - One of the best experts on this subject based on the ideXlab platform.
-
Detailed Flow Study of Mach Number 1.6 High Transonic Flow With a Shock Wave in a Pressure Ratio 11 Centrifugal Compressor Impeller
Journal of Turbomachinery, 2004Co-Authors: Hirotaka Higashimori, Kunio Sumida, Kiyoshi Hasagawa, Tooru SuitaAbstract:Requirements for aeronautical gas turbine engines for helicopters\ninclude small size, low weight, high output, and low fuel consumption.\nIn order to achieve these requirements, development work has been\ncarried out on high efficiency and high pressure ratio compressors.\nAs a result, we have developed a single stage centrifugal compressor\nwith a pressure ratio of 11 for a 1000 shp class gas turbine. The\ncentrifugal compressor is a high transonic compressor with an Inlet\nMach number of about 1.6. In high Inlet Mach number compressors,\nthe flow distortion due to the shock wave and the shock boundary\nlayer interaction must have a large effect on the flow in the inducer.\nIn order to ensure the reliability of aerodynamic design technology,\nthe actual supersonic flow phenomena with a shock wave must be ascertained\nusing measurement and CFD. This report presents the measured results\nof the high transonic flow at the Impeller Inlet using LDV and verification\nof CFD, with respect to the high transonic flow velocity distribution,\npressure distribution and shock boundary layer interaction at the\ninducer. The Impeller Inlet tangential velocity is about 460m/s and\nthe relative Mach number reaches about 1.6. Using an LDV, about 500m/s\nrelative velocity was measured preceding a steep deceleration of\nvelocity. The following steep deceleration of velocity at the middle\nof blade pitch clarified the cause as being the pressure rise of\na shock wave, through comparison with CFD as well as comparison with\nthe pressure distribution measured using a high frequency pressure\ntransducer. Furthermore, a reverse flow is measured in the vicinity\nof casing surface. It was clarified by comparison with CFD that the\nreverse flow is caused by the shock-boundary layer interaction. Generally\nCFD shows good agreement with the measured velocity distribution\nat the inducer and splitter Inlet, except in the vicinity of the\ncasing surface.
Junichi Kurokawa - One of the best experts on this subject based on the ideXlab platform.
-
Inlet Reverse-Flow Model Theoretical Head and of Mixed-Flow
1994Co-Authors: Junichi Kurokawa, Jie Jiang, Takaya KitahoraAbstract:In order to predict performances of mixed-flow purnps over the whole discharge range, it is necessary to establish a calculation method of theoretical head and power 10ss caused by a reverse flow at the Inlet and the outlet of an irnpeller. In this report, a reverse flow model at an Impeller Inlet is proposed together with the dependence of the slip factor upon discharge, and a prediction method of theoretical head and water power of mixed-flow pumps by a simple calculation is presented using this Inlet reverse flow model. The comparison with the measurements revealed that the present method yields a good prediction for the Inlet velocity distribution and for the theoretical head and water power in the whole discharge range.
-
Inlet Reverse Flow Model and Prediction of Theoretical Head and Water Power of Mixed-Flow Pumps.
Transactions of the Japan Society of Mechanical Engineers. B, 1993Co-Authors: Junichi Kurokawa, Jie Jiang, Takaya KitahoraAbstract:In order to predict the performance of mixed-flow pumps over the whole flow-rate range, it is necessary to establish a calculation method of theoretical head and water power loss caused by a reverse flow at the Inlet and the outlet of an Impeller. In this report, a reverse flow model at the Impeller Inlet is proposed together with a slip factor formula, and a prediction of theoretical head and water power of mixed-flow pumps is presented by a simple one-dimensional calculation using this Inlet flow model. The results show that the present method gives a good estimation for the Inlet velocity distributions and for the theoretical head and water power in the whole flow-rate range.
-
Inlet and Outlet Flow of a Mixed-Flow Pump.
Transactions of the Japan Society of Mechanical Engineers. B, 1992Co-Authors: Jie Jiang, Junichi KurokawaAbstract:In order to establish a performance prediction method of mixed-flow pumps in all flow ranges, the Inlet and outlet flow characteristics are measured and the characteristics of Inlet reverse flow in low flow range are discussed, as it exerts remarkable influence on the performance. The reverse flow characteristics at the Impeller Inlet are determined experimentally, and their influence on the theoretical head is discussed.
