Three Dimensional Velocity Measurements by Laser Anemometry in a Diesel Engine Cylinder Under Steady State Inlet Flow Conditions

1978 ◽  
Author(s):  
G. Wigley ◽  
M. G. Hawkins
Keyword(s):  
Steady State ◽  
Diesel Engine ◽  
Three Dimensional ◽  
Flow Conditions ◽  
Velocity Measurements ◽  
Inlet Flow ◽  
Laser Anemometry ◽  
Engine Cylinder

The Effect of Stator-Rotor Hub Sealing Flow on the Mainstream Aerodynamics of a Turbine

2006 ◽  
Author(s):  
Kevin Reid ◽  
John Denton ◽  
Graham Pullan ◽  
Eric Curtis ◽  
John Longley
Keyword(s):  
Steady State ◽  
Entropy Generation ◽  
Flow Rate ◽  
Three Dimensional ◽  
Secondary Flows ◽  
Flow Conditions ◽  
Turbine Efficiency ◽  
Turbine Performance ◽  
Mainstream Flow ◽  
Flow Interactions

An investigation into the effect of stator-rotor hub gap sealing flow on turbine performance is presented. Efficiency measurements and rotor exit area traverse data from a low speed research turbine are reported. Tests carried out over a range of sealing flow conditions show that the turbine efficiency decreases with increasing sealant flow rate but that this penalty is reduced by swirling the sealant flow. Results from time-accurate and steady-state simulations using a three-dimensional multi-block RANS solver are presented with particular emphasis paid to the mechanisms of loss production. The contributions toward entropy generation of the mixing of the sealant fluid with the mainstream flow and of the perturbed rotor secondary flows are assessed. The importance of unsteady stator wake/sealant flow interactions is also highlighted.

Effect of Shroud and Orientation Angles of Inlet Valve on Flow Characteristic Through Helical–Spiral Inlet Port in Diesel Engine

2017 ◽  
Vol 139 (10) ◽  
Author(s):  
A. Abd El-Sabor Mohamed ◽  
Saleh Abo-Elfadl ◽  
Abd El-Moneim M. Nassib
Keyword(s):  
Diesel Engine ◽  
Three Dimensional ◽  
Orientation Angle ◽  
Combustion Efficiency ◽  
Inlet Valve ◽  
Maximum Increase ◽  
Inlet Port ◽  
A Value ◽  
Engine Cylinder ◽  
Dimensional Simulation

The in-cylinder airflow motion is an important factor that severely affects combustion efficiency and emissions in diesel engines. It is greatly affected by the inlet port and valve geometries. A diesel engine cylinder with a helical–spiral inlet port is used in this study. An ordinary inlet valve and shrouded inlet valve having different shroud and orientation angles are used to study the shroud effect on the swirl and tumble motion inside the engine cylinder. Four shroud angles of 90 deg, 120 deg, 150 deg, and 180 deg are used. With each shroud angle, four orientation angles of 0 deg, 30 deg, 60 deg, and 90 deg are also used. Three-dimensional simulation model using the shear stress transport (SST) k–ω model is used for simulating air flow through the inlet port, inlet valve, and engine cylinder during both the intake and compression strokes. The results showed that increasing the valve shroud angle increases the swirl, and the maximum increase occurs at a valve shroud angle of 180 deg and orientation angle of 0 deg with a value of 80% with respect to the ordinary valve. But it decreases the volumetric efficiency, and the maximum decrement occurs at valve shroud of 180 deg and orientation angle of 90 deg with a value of 5.98%. Variations of the shroud and orientation angles have very small effect on the tumble inside the engine cylinder.

Numerical Simulations of Flow in Cerebral Aneurysms: Comparison of CFD Results and In Vivo MRI Measurements

2008 ◽  
Vol 130 (5) ◽  
Author(s):  
Vitaliy L. Rayz ◽  
Loic Boussel ◽  
Gabriel Acevedo-Bolton ◽  
Alastair J. Martin ◽  
William L. Young ◽  
...  
Keyword(s):  
Flow Fields ◽  
Patient Specific ◽  
Flow Ratio ◽  
Flow Conditions ◽  
Velocity Measurements ◽  
Cfd Simulations ◽  
Specific Flow ◽  
Inlet Flow ◽  
Good Agreement

Computational fluid dynamics (CFD) methods can be used to compute the velocity field in patient-specific vascular geometries for pulsatile physiological flow. Those simulations require geometric and hemodynamic boundary values. The purpose of this study is to demonstrate that CFD models constructed from patient-specific magnetic resonance (MR) angiography and velocimetry data predict flow fields that are in good agreement with in vivo measurements and therefore can provide valuable information for clinicians. The effect of the inlet flow rate conditions on calculated velocity fields was investigated. We assessed the internal consistency of our approach by comparing CFD predictions of the in-plane velocity field to the corresponding in vivo MR velocimetry measurements. Patient-specific surface models of four basilar artery aneurysms were constructed from contrast-enhanced MR angiography data. CFD simulations were carried out in those models using patient-specific flow conditions extracted from MR velocity measurements of flow in the inlet vessels. The simulation results computed for slices through the vasculature of interest were compared with in-plane velocity measurements acquired with phase-contrast MR imaging in vivo. The sensitivity of the flow fields to inlet flow ratio variations was assessed by simulating five different inlet flow scenarios for each of the basilar aneurysm models. In the majority of cases, altering the inlet flow ratio caused major changes in the flow fields predicted in the aneurysm. A good agreement was found between the flow fields measured in vivo using the in-plane MR velocimetry technique and those predicted with CFD simulations. The study serves to demonstrate the consistency and reliability of both MR imaging and numerical modeling methods. The results demonstrate the clinical relevance of computational models and suggest that realistic patient-specific flow conditions are required for numerical simulations of the flow in aneurysmal blood vessels.

Free Modal Analysis of a 2-Cylinder Diesel Engine Cylinder Block

2010 ◽  
Vol 29-32 ◽  
pp. 310-314
Author(s):  
Zhong Cai Zheng ◽  
Na Liu ◽  
Yan Gao ◽  
Kun Jin Zhang ◽  
Hai Ou Chen
Keyword(s):  
Diesel Engine ◽  
Modal Analysis ◽  
Three Dimensional ◽  
Engine Block ◽  
Cylinder Block ◽  
Mode Shapes ◽  
Relative Distribution ◽  
Three Dimensional Model ◽  
Engine Cylinder ◽  
Vibration Magnitude

The three dimensional model of a 2-cylinder diesel engine block is established with the P ro/E software, and then the modal analysis of the engine block is carried out using finite element method with ANSYS software . Through the analysis, the inherent frequencies and mode shapes of the first 6 order modes are obtained respectively, and then are compared with the testing result; comparison shows the results of FEA estimation are in good agreement with those of testing which indicates the FEA results’ correctness. The results of the relative distribution of the vibration magnitude in the whole block are given, which provide necessary guides for the dynamic optimal design of the engine block.

Study of the Steady-State Flow Pattern in a Multipulse Converter by LDA

1988 ◽  
Vol 110 (3) ◽  
pp. 515-522 ◽  
Author(s):  
P. Flamang ◽  
R. Sierens
Keyword(s):  
Steady State ◽  
Cross Sections ◽  
Laser Doppler Anemometry ◽  
Three Dimensional ◽  
Velocity Measurements ◽  
Pulse Converter ◽  
Flow Situation ◽  
Flow Configurations ◽  
Pressure And Velocity Measurements ◽  
Mixing Losses

This paper describes pressure and velocity measurements on a multipulse converter under steady-state conditions. Pressure loss coefficients were measured on this four-entry pulse converter system for a large number of flow configurations. Three-dimensional velocity measurements were done (with Laser-Doppler anemometry) for several flow configurations and at different cross sections in the converter. The normal flow situation (incoming flow at the four entries) and back flow situations were examined. For each cross section the axial velocity profiles, the secondary flow patterns, and the turbulent velocities are presented. From the pressure measurements mixing losses are derived. These are compared with the results of a one-dimensional calculation, which is based on the impulse law for incompressible flow. Taking into account the velocity measurements, this simplified model gives a remarkable agreement with the measured mixing losses.

Inverse Design of Centrifugal Compressor Vaned Diffusers in Inlet Shear Flows

1996 ◽  
Vol 118 (2) ◽  
pp. 385-393 ◽  
Author(s):  
M. Zangeneh
Keyword(s):  
Flow Field ◽  
Centrifugal Compressor ◽  
Design Method ◽  
Three Dimensional ◽  
Internal Flow ◽  
Inviscid Flow ◽  
Inverse Design ◽  
Flow Conditions ◽  
Inlet Flow ◽  
Blade Thickness

A three-dimensional inverse design method in which the blade (or vane) geometry is designed for specified distributions of circulation and blade thickness is applied to the design of centrifugal compressor vaned diffusers. Two generic diffusers are designed, one with uniform inlet flow (equivalent to a conventional design) and the other with a sheared inlet flow. The inlet shear flow effects are modeled in the design method by using the so-called “Secondary Flow Approximation” in which the Bernoulli surfaces are convected by the tangentially mean inviscid flow field. The difference between the vane geometry of the uniform inlet flow and nonuniform inlet flow diffusers is found to be most significant from 50 percent chord to the trailing edge region. The flows through both diffusers are computed by using Denton’s three-dimensional inviscid Euler solver and Dawes’ three-dimensional Navier–Stokes solver under sheared in-flow conditions. The predictions indicate improved pressure recovery and internal flow field for the diffuser designed for shear inlet flow conditions.

Determination of the Pressure Field Using Three-Dimensional, Volumetric Velocity Measurements

2016 ◽  
Vol 138 (8) ◽  
Author(s):  
Hansheng Pan ◽  
Sheila H. Williams ◽  
Paul S. Krueger
Keyword(s):  
Poisson Equation ◽  
Temporal Resolution ◽  
Pressure Field ◽  
Three Dimensional ◽  
Vortical Flow ◽  
Flow Conditions ◽  
Velocity Measurements ◽  
Pressure Poisson Equation ◽  
Computational Fluid Dynamics Cfd

Methods to determine the pressure field of vortical flow from three-dimensional (3D) volumetric velocity measurements (e.g., from a TSI V3VTM system) are discussed. The boundary pressure was determined where necessary using the unsteady Bernoulli equation for both line integration and pressure Poisson equation methods. Error analysis using computational fluid dynamics (CFD) data was conducted to investigate the effects of spatial resolution, temporal resolution, and velocity error levels. The line integration method was more sensitive to temporal resolution, while the pressure Poisson equation method was more sensitive to boundary flow conditions. The latter was generally more suitable for V3VTM velocity measurements.

An Experimental Study of Natural Convection in a Toroidal Loop

1988 ◽  
Vol 110 (4a) ◽  
pp. 877-884 ◽  
Author(s):  
C. H. Stern ◽  
R. Greif ◽  
J. A. C. Humphrey
Keyword(s):  
Experimental Study ◽  
Three Dimensional ◽  
Secondary Flows ◽  
Laser Doppler Velocimeter ◽  
Temperature Profiles ◽  
Flow Conditions ◽  
Velocity Measurements ◽  
Heating Section ◽  
Thermocouple Probe ◽  
Flow Reversals

Velocity and temperature profiles were measured at the entrance and exit to the heating section of a toroidal thermosyphon loop operating under steady flow conditions for a range of heat inputs. Velocity measurements were made with a laser-Doppler velocimeter and temperature measurements with a small thermocouple probe. Detailed results are presented for the longitudinal and circumferential components of the velocity for four heat inputs. The data for cross-stream secondary flows and streamwise flow reversals emphasize the importance of including three-dimensional effects in analyses of these systems.

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