The Experts below are selected from a list of 65103 Experts worldwide ranked by ideXlab platform
Wang Dalei - One of the best experts on this subject based on the ideXlab platform.
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simulation of Inlet total Pressure distortion in a transonic compressor rotor
Computer Simulation, 2010Co-Authors: Wang DaleiAbstract:Inlet Pressure distortion can seriously deteriorate the stability of compressors.Three-Dimensional numerical simulations were carried out to a transonic compressor rotor at different steady-state Inlet total Pressure distortion conditions.And the influence of circumferential total Pressure Inlet distortion at three representative speeds was emphasized.Detail analyses of the rotor flow field came to some preliminary conclusions: Radial tip distortion deteriorates the performance and the stability of the rotor more than the others at design rotation speed.And radial hub distortion improves the rotor stall margin.Circumferential Inlet total Pressure distortion makes the efficiency and margin of the rotor descend at three different rotation speeds.And as the rotation speed drops the efficiency and stall margin reduce more.
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numerical simulation of the effect of total Pressure Inlet distortion on a compressor rotor
Journal of Aerospace Power, 2009Co-Authors: Wang DaleiAbstract:Steady numerical simulation of the flow field of the Rotor37 with total Pressure distortion Inlet was conducted by resolving three dimensional Navier-Stokes functions in this paper.Three different low total Pressure Inlet conditions were considered: one distortion per revolution(1×120°),two distortions per revolution(2×60°) and four distortions per revolution(4×30°).The characteristics of the rotor with total Pressure distortion were achieved.Influences of different frequencies of distortion were considered.The flow field of the rotor was analyzed in detail,and some preliminary conclusions were made: circumferential Pressure distortion causes non-uniformity of other Inlet parameters.The Inlet total Pressure induces total temperature distortion at the outlet.Massflow and efficiency decrease,and stall margin increases as the frequencies of distortion increase with the total spoiled sector of 120 degrees.Stability total Pressure ratio depends only on the angle of the distorted sector and the loss of the stability total Pressure ratio increases with the growing angle of the distorted sector.
Andreas Hunig - One of the best experts on this subject based on the ideXlab platform.
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application of an o ring pinch device as a constant Pressure Inlet cpi for airborne sampling
Atmospheric Measurement Techniques Discussions, 2020Co-Authors: Sergej Molleker, Frank Helleis, Thomas Klimach, Oliver Appel, Hanschristian Clemen, Antonis Dragoneas, C Gurk, Andreas HunigAbstract:Abstract. We present a novel and compact design of a constant Pressure Inlet (CPI) developed for use in airborne aerosol mass spectrometry. In particular the Inlet system is optimized for aerodynamic lenses commonly used in aerosol mass spectrometers, where efficient focusing of aerosol particles into a vacuum chamber requires a precisely controlled lens Pressure, typically of a few hPa. The CPI device can also be used in gas phase sampling instruments in a large range of altitude and Inlet Pressure. The constant Pressure is achieved by changing the inner diameter of a properly scaled O-ring that acts as a critical orifice. The CPI control keeps air Pressure and thereby mass flow rate (≈ 0.1 l/min) upstream of an aerodynamic lens constant, deviating at most by only p 2 % from a pre-set value. In our setup a Pressure sensor downstream of the O-ring controls the pinch mechanism via a feedback loop and setpoint conditions are reached within seconds. The device was implemented in a few instruments, which were successfully operated on different research aircraft covering a wide range of ambient Pressures, from sea level up to about 55 hPa. Details of operation and quality of aerosol particle transmission are evaluated by laboratory experiments and in-flight data with a single particle mass spectrometer.
Antonis Dragoneas - One of the best experts on this subject based on the ideXlab platform.
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application of an o ring pinch device as a constant Pressure Inlet cpi for airborne sampling
Atmospheric Measurement Techniques Discussions, 2020Co-Authors: Sergej Molleker, Frank Helleis, Thomas Klimach, Oliver Appel, Hanschristian Clemen, Antonis Dragoneas, C Gurk, Andreas HunigAbstract:Abstract. We present a novel and compact design of a constant Pressure Inlet (CPI) developed for use in airborne aerosol mass spectrometry. In particular the Inlet system is optimized for aerodynamic lenses commonly used in aerosol mass spectrometers, where efficient focusing of aerosol particles into a vacuum chamber requires a precisely controlled lens Pressure, typically of a few hPa. The CPI device can also be used in gas phase sampling instruments in a large range of altitude and Inlet Pressure. The constant Pressure is achieved by changing the inner diameter of a properly scaled O-ring that acts as a critical orifice. The CPI control keeps air Pressure and thereby mass flow rate (≈ 0.1 l/min) upstream of an aerodynamic lens constant, deviating at most by only p 2 % from a pre-set value. In our setup a Pressure sensor downstream of the O-ring controls the pinch mechanism via a feedback loop and setpoint conditions are reached within seconds. The device was implemented in a few instruments, which were successfully operated on different research aircraft covering a wide range of ambient Pressures, from sea level up to about 55 hPa. Details of operation and quality of aerosol particle transmission are evaluated by laboratory experiments and in-flight data with a single particle mass spectrometer.
Oliver Appel - One of the best experts on this subject based on the ideXlab platform.
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application of an o ring pinch device as a constant Pressure Inlet cpi for airborne sampling
Atmospheric Measurement Techniques Discussions, 2020Co-Authors: Sergej Molleker, Frank Helleis, Thomas Klimach, Oliver Appel, Hanschristian Clemen, Antonis Dragoneas, C Gurk, Andreas HunigAbstract:Abstract. We present a novel and compact design of a constant Pressure Inlet (CPI) developed for use in airborne aerosol mass spectrometry. In particular the Inlet system is optimized for aerodynamic lenses commonly used in aerosol mass spectrometers, where efficient focusing of aerosol particles into a vacuum chamber requires a precisely controlled lens Pressure, typically of a few hPa. The CPI device can also be used in gas phase sampling instruments in a large range of altitude and Inlet Pressure. The constant Pressure is achieved by changing the inner diameter of a properly scaled O-ring that acts as a critical orifice. The CPI control keeps air Pressure and thereby mass flow rate (≈ 0.1 l/min) upstream of an aerodynamic lens constant, deviating at most by only p 2 % from a pre-set value. In our setup a Pressure sensor downstream of the O-ring controls the pinch mechanism via a feedback loop and setpoint conditions are reached within seconds. The device was implemented in a few instruments, which were successfully operated on different research aircraft covering a wide range of ambient Pressures, from sea level up to about 55 hPa. Details of operation and quality of aerosol particle transmission are evaluated by laboratory experiments and in-flight data with a single particle mass spectrometer.
Joshua P Schlegel - One of the best experts on this subject based on the ideXlab platform.
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experimental investigation of natural circulation instability in a bwr type small modular reactor
Progress in Nuclear Energy, 2015Co-Authors: Joshua P Schlegel, Caleb S Brooks, Takashi Hibiki, Mamoru IshiiAbstract:Abstract The Purdue NMR (Novel Modular Reactor) represents a BWR-type small modular reactor with a significantly reduced reactor Pressure vessel (RPV). Specifically, the NMR is one third the height and area of a conventional BWR RPV with an electrical output of 50 MWe. Experiments are performed in a well-scaled test facility to investigate the thermal hydraulic flow instabilities during the startup transients for the NMR. The scaling analysis for the design of natural circulation test facility uses a three-level scaling methodology. Scaling criteria are derived from non-dimensional field and constitutive equations. Important thermal hydraulic parameters, e.g. system Pressure, Inlet coolant flow velocity and local void fraction, are analyzed for slow and fast normal startup transients. Flashing instability and density wave oscillation are the main flow instabilities observed when system Pressure is below 0.5 MPa. And the flashing instability and density wave oscillation show different type of oscillations in void fraction profile. Finally, the pressurized startup procedure is recommended and tested in current research to effectively eliminate the flow instabilities during the NMR startup transients.