Measurement of flow angle and mass flow rate in an unknown flow field using hot film and hot wire probes

1978 ◽  
Author(s):  
V. HELMS, III
Keyword(s):  
Flow Field ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Hot Wire ◽  
Flow Angle ◽  
Hot Film

A physics-based zero-dimensional model for the mass flow rate of a turbocharger compressor with uniform/distorted inlet condition

2018 ◽  
Vol 20 (6) ◽  
pp. 624-639 ◽  
Author(s):  
Kang Song ◽  
Ben Zhao ◽  
Harold Sun ◽  
Weilin Yi
Keyword(s):  
Flow Field ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Fluid Dynamic ◽  
Dimensional Model ◽  
Inlet Pipe ◽  
External Work ◽  
Compressor Wheel ◽  
Inlet Flow

Turbocharger compressor, when fitted to a vehicle, usually operates with a curved inlet pipe which leads to distorted inlet flow field, hence deteriorating compressor flow capability. During the measurement of compressor performance, turbocharger-engine matching and controller design, the inlet flow field is, however, assumed to be uniform, which deviates from the real-world conditions. Consequently, the overall system performance could be compromised if the inlet distortion effect is ignored. To address this issue, in this article, a turbomachinery physics-based zero-dimensional model was proposed for the mass flow rate of a compressor with distorted inlet flow field due to 90° and 180° bent inlet pipe. The non-uniform flow is approximated as two-zone flow field, similar to parallel compressors, with the total pressure deviation between two zones modeled as a function of the flow velocity and pipe geometry. For each flow zone, the corresponding mass flow rate is estimated by approximating each sub-compressor as an adiabatic nozzle, where the fluid is driven by external work delivered by a compressor wheel governed by Euler’s turbomachinery equation. By including turbomachinery physics and compressor geometry information into the modeling, the model achieves high fidelity in compressor map interpretation and extrapolation, which is validated in experiments and the three-dimensional computational fluid dynamic simulation.

Mass flow-rate control unit to calibrate hot-wire sensors

2007 ◽  
Vol 44 (2) ◽  
pp. 189-197 ◽  
Author(s):  
F. Durst ◽  
K. Haddad ◽  
A. Al-Salaymeh ◽  
Shadi Eid ◽  
B. Ünsal
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Rate Control ◽  
Control Unit ◽  
Hot Wire ◽  
Flow Rate Control

Investigation of Flow Field at the Inlet of a Turbocharger Compressor Using Digital Particle Image Velocimetry

2019 ◽  
Vol 141 (12) ◽  
Author(s):  
Deb Banerjee ◽  
Rick Dehner ◽  
Ahmet Selamet ◽  
Kevin Tallio ◽  
Keith Miazgowicz ◽  
...  
Keyword(s):  
Particle Image Velocimetry ◽  
Flow Field ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Particle Image ◽  
Flow Reversal ◽  
High Mass ◽  
Reversed Flow ◽  
Image Velocimetry

Abstract The flow field at the inlet of a turbocharger compressor has been studied through stereoscopic particle image velocimetry (SPIV) experiments under different operating conditions. It is found that the flow field is quite uniform at high mass flow rates; but as the mass flow rate is reduced, flow reversal from the impeller is observed as an annular ring at the periphery of the inlet duct. The inception of flow reversal is observed to occur in the mid-flow operating region, near peak efficiency, and corresponds to an incidence angle of about 15.5 deg at the inducer blade tips at all tested speeds. This reversed flow region is marked with high tangential velocity and rapid fluctuations. It grows in strength with reducing mass flow rate and imparts some of its angular momentum to the forward flow due to mixing. The penetration depth of the reversed flow upstream from the inducer plane is found to increase quadratically with decreasing flow rate.

Condensation flow at the wet steam centrifugal turbine stage

2019 ◽  
Vol 234 (8) ◽  
pp. 1108-1121 ◽  
Author(s):  
Yaping Liu ◽  
Xuefei Du ◽  
Xuyang Shi ◽  
Diangui Huang
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Three Dimensional ◽  
Velocity Slip ◽  
Aerodynamic Characteristics ◽  
Nucleation Theory ◽  
Wet Steam ◽  
Flow Angle ◽  
Shaft Power

This paper investigates spontaneous condensation of wet steam in a centrifugal turbine by means of three-dimensional computational fluid dynamics. The flow field and aerodynamic characteristics of the wet steam in the centrifugal turbine are compared and analyzed by using the equilibrium steam and nonequilibrium steam models, respectively, where the latter applies the classical droplet nucleation theory and neglects velocity slip between the liquid phase and the gaseous phase. The state parameters of wet steam are described here based on the IAPWS’97 formulation. It is concluded that under the design condition, the mass flow rate, wetness fraction, and flow angle of the wet steam centrifugal turbine in the nonequilibrium steam model all change compared with the equilibrium steam model, with values of 4.4%, 0.5%, and 10.57%, respectively. Then the performance variation of the wet steam centrifugal turbine is analyzed under different steam conditions and different outlet back-pressure conditions. The results show that the change law of the mass flow rate, shaft power, and wetness fraction in the centrifugal turbine are basically identical in both models, and the mass flow rate, shaft power, wheel efficiency, and entropy loss coefficient of the centrifugal turbine in the nonequilibrium steam model are all higher than those in the equilibrium steam model, whereas the outlet wetness fraction is lower than that in the equilibrium steam model.

Numerical Simulation of Flow Field Dynamics Characteristics for One Novel Twin-Screw Kneader

2012 ◽  
Vol 271-272 ◽  
pp. 1049-1055
Author(s):  
Jing Wei ◽  
Xin Long Liang ◽  
Wei Sun ◽  
Li Cun Wang
Keyword(s):  
Numerical Simulation ◽  
Shear Stress ◽  
Flow Field ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Maximum Shear Stress ◽  
Twin Screw ◽  
Screw Rotors ◽  
Center Distance

The numerical simulation for dynamic characteristics of the flow field of a novel twin-screw kneader is carried out. The flow field model of the twin-screw kneader is established, and the three-dimensional, isothermal and steady numerical analysis of non-Newtonian fluid is presented based on computational fluid dynamics (CFD) theory, and the characteristics under the conditions of different speeds and center distances such as the distribution of pressure and velocity field, the maximum shear stress, the mass flow rate and so on, are studied. The research results show that: with increasing speed, the maximum flow pressure, the mass flow rate, the maximum shear stress will increase; the maximum shear stress increases first and then decreases with increasing of center distance of the screw rotors, while the mass flow rate increases with increasing of center distance; but when the center distance reaches a certain degree, the mass flow rate will be negative and the material will appear serious reflux which can lead the kneader to stopping working.

An Actuator Disk Model of Incidence and Deviation for RANS-Based Throughflow Analysis

2013 ◽  
Vol 136 (2) ◽  
Author(s):  
Simone Rosa Taddei ◽  
Francesco Larocca
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Total Pressure ◽  
Operating Conditions ◽  
Finite Volume Scheme ◽  
Disk Model ◽  
Flow Angle ◽  
Actuator Disk ◽  
Shaft Power

Reynolds-averaged Navier–Stokes (RANS) equations with blade blockage and blade force source terms are solved in the meridional plane of complete axial flow turbomachinery using a finite-volume scheme. The equations of the compressible actuator disk (AD) are introduced to modify the evaluation of the convective fluxes at the leading and trailing edges (LEs and TEs). An AD behaves as a compact blade force which instantaneously turns the flow with no production of unphysical entropy. This avoids unphysical incidence loss across the LE discontinuity and allows for application of all of the desired deviation at the TE. Unlike previous treatments, the model needs no handmade modification of the throughflow (TF) surface and does not discriminate between inviscid and viscous meridional flows, which allows for coping with strong incidence gradients through the annulus wall boundary layers and with secondary deviation. This paper derives a generalized blade force term that includes the contribution of the LE and TE ADs in the divergence form of the TF equations and leads to generalized definitions of blade load, blade thrust, shaft torque, and shaft power. In analyzing a linear flat plate cascade with an incidence of 32 deg and a deviation of 21 deg, the proposed model provided a 105 reduction of unphysical total pressure loss compared to the numerical solution with no modeling. The computed mass flow rate, blade load, and blade thrust showed excellent agreement with the theoretical values. The complete RANS TF solver was used to analyze a four-stage turbine in design and off-design conditions with a spanwise-averaged incidence of up to 2 deg and 43 deg, respectively. Compared to a traditional streamline curvature solution, the RANS solution with incidence and deviation modeling provided a 0.1 to 0.7% accurate prediction of mass flow rate, shaft power, total pressure ratio, and adiabatic efficiency in both the operating conditions. It also stressed satisfactory agreement concerning the spanwise distributions of flow angle and Mach number at LEs and TEs. In particular, secondary deviation was effectively predicted. The RANS solution with no modeling showed acceptable performance prediction only in design conditions and could introduce no deviation.

Effects of Slot Bleed Injection Over a Contoured Endwall on Nozzle Guide Vane Cooling Performance: Part I — Flow Field Measurements

2000 ◽  
Author(s):  
Steven W. Burd ◽  
Terrence W. Simon
Keyword(s):  
Flow Field ◽  
Secondary Flow ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Large Scale ◽  
Secondary Flows ◽  
Cooling Flow ◽  
Nozzle Guide ◽  
Aerodynamic Losses

Film cooling and secondary flows are major contributors to aerodynamic losses in turbine passages. This is particularly true in low aspect ratio nozzle guide vanes where secondary flows can occupy a large portion of the passage flow field. To reduce losses, advanced cooling concepts and secondary flow control techniques must be considered. To this end, combustor bleed cooling flows introduced through an inclined slot upstream of the airfoils in a nozzle passage were experimentally investigated. Testing was performed in a large-scale, high-pressure turbine nozzle cascade comprised of three airfoils between one contoured and one flat endwall. Flow was delivered to this cascade with high-level (∼9%), large-scale turbulence at a Reynolds number based on inlet velocity and true chord length of 350,000. Combustor bleed cooling flow was injected through the contoured endwall upstream of the contouring at bleed-to-core mass flow rate ratios ranging from 0 to 6%. Measurements with triple-sensor, hot-film anemometry characterize the flow field distributions within the cascade. Total and static pressure measurements document aerodynamic losses. The influences of bleed mass flow rate on flow field mean streamwise and cross-stream velocities, turbulence distributions, and aerodynamic losses are discussed. Secondary flow features are also described through these measurements. Notably, this study shows that combustor bleed cooling flow imposes no aerodynamic penalty. This is atypical of schemes where coolant is introduced within the passage for the purpose of endwall cooling. Also, instead of being adversely affected by secondary flows, this type of cooling is able to reduce secondary flow effects.

Sensitivity Analysis of Turbulence Models for the Core Inlet Flow Distribution of PWR

2018 ◽  
Author(s):  
Lu-lu Hao ◽  
Hong Chen ◽  
Su chen Qiu
Keyword(s):  
Flow Field ◽  
Mass Flow Rate ◽  
Turbulence Model ◽  
Mass Flow ◽  
Flow Rate ◽  
Mesh Generation ◽  
Flow Distribution ◽  
Computation Model ◽  
Pressurized Water ◽  
Geometry Model

Computational Fluid Dynamics (CFD) methods have been developed into effective fluid simulation means to be used on the hydraulic design in the field of nuclear reactor. However, it is difficult to generate suitable mesh and select turbulence model for simulation because of the complex geometry structure and flow behavior in the pressure vessel. Based on CFX software, a hydraulic computation model of typical pressurized water reactor is established and the flow distribution at core inlet is analyzed. The simplified geometry model consists cold legs, downcomer, lower plenum, secondary support component, core support plate, and lower core plate. The computation model is divided into three parts for mesh generation, including the part of inlet and downcomer, the part of lower plenum and core inlet section, and the part of core. In order to reach the independence of grid several methods of mesh generation which contains different mesh density at local key parties are investigated to screen out the suitable mesh scheme. The k-ε, k-ω, and SST k-ω turbulence model are respectively used for simulation and the sensitivity of turbulence model at different locations of flow field is analyzed. The results show that the mass flow rate of the near wall flow field, computed by using k-ω turbulence model, is consistent with SST k-ω model, while the mass flow rate of central flow field computed by using k-ε turbulence agrees with SST k-ω model. The result computed by using k-ε turbulence model shows relatively uniform flow distribution at core inlet, which is more consistent with the measured data with the average difference of 3.1%. By using the k-ε model, the probability distribution of the difference between the calculated results and the experimental values follows the law of Normal distribution. The final coolant flow distribution at each orifice is evaluated, and the maximum normalized flow flux is found at center orifice while the flow rate at the edge of core is relatively lower.

Hybrid Pressure-Swirl/Twin-Fluid Atomizer for Emission Controls

2006 ◽  
Author(s):  
Andrew C. S. Lee ◽  
Paul E. Sojka
Keyword(s):  
Flow Field ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Drop Size ◽  
Air Flow ◽  
Exit Plane ◽  
Swirl Atomizer ◽  
Pressure Swirl ◽  
Pressure Swirl Atomizer

An experimental study was conducted to characterize the performance of a hybrid atomizer used in emission control devices. Characterization included drop size distribution, measured using a forward light-scattering instrument, the air flow field (axial and radial velocities), measured using 2-D PIV, and turbulence characteristics of the air flow field, measured using LDA. The air flow field showed characteristics common to turbulent free round jets beyond approximately 8 exit orifice diameters from the atomizer exit plane. The centerline velocity increased with an increase in mass flow rate, while radial velocities were two orders of magnitude smaller than centerline values. The jet spreading factor initially increased with an increase in axial distance from the exit; however, it stabilized at a value of 0.09 at z/Do=11.8. Turbulence intensity along the jet centerline stabilized at 25% at z/Do=7.9. Drop size data showed complex dependencies on liquid and air mass flow rates, and on internal geometry. The influence of liquid mass flow rate on drop size was significantly smaller for the hybrid atomizer than for the pressure swirl atomizer component housed inside the hybrid unit, thus indicating a higher turndown ratio for the hybrid device. Drop size distributions produced by the hybrid atomizer showed multiple peaks, indicating there is more than one important atomizing mechanism. Finally, reducing the gap between the pressure-swirl atomizer and the exit plane of the outer casing resulted in a reduction in drop size.

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