The Effect of Inlet Velocity Distribution and Magnitude on In-Cylinder Turbulence Intensity and Burn Rate—Model Versus Experiment

1988 ◽  
Vol 110 (3) ◽  
pp. 509-514 ◽  
Author(s):  
G. C. Davis ◽  
R. J. Tabaczynski
Keyword(s):  
Turbulence Intensity ◽  
Mass Flux ◽  
Discharge Coefficient ◽  
Intake Valve ◽  
Flow Measurements ◽  
Inlet Velocity ◽  
Mass Distributions ◽  
Engine Simulation ◽  
Model Versus ◽  
Burn Rate

Steady flow measurements of velocity and mass flux distributions around the intake valve were used as input to a General Engine Simulation Model (GESIM) to assess the assumptions of uniform velocity and mass flux distributions and their effects on in-cylinder turbulence intensity and burn rate. In addition, an improved submodel for calculating the instantaneous velocity past the intake valve was developed and its effects on intake generated turbulence and burn rate assessed. Using the improved, inlet velocity submodel, a study was carried out for three different intake port configurations. Burn rate measurements were compared with model results for these configurations, which utilized the same engine head and block assembly. Model predictions, based on the standard port/valve discharge coefficient, indicated that velocity and mass distributions alone had a small effect on the in-cylinder turbulence intensity and burn rate. Significant differences in burn rate and turbulence intensity were predicted when the improved submodel for valve discharge coefficient was used. The new predictions agreed well with experimental measurements of burn rate. This implies that the increased mean velocities (which occur due to the restriction that creates the velocity and mass flow distributions) are the major cause for increased turbulence levels.

Analysis of Variable Intake Runner Lengths and Intake Valve Open Timings on Engine Performances

2014 ◽  
Vol 663 ◽  
pp. 336-341 ◽  
Author(s):  
Mohd Farid Muhamad Said ◽  
Zulkarnain Abdul Latiff ◽  
Aminuddin Saat ◽  
Mazlan Said ◽  
Shaiful Fadzil Zainal Abidin
Keyword(s):  
Engine Performance ◽  
Intake Manifold ◽  
Intake Valve ◽  
Si Engine ◽  
Engine Simulation ◽  
Engine Model ◽  
Optimum Parameters ◽  
Comparison Results ◽  
Variable Valve ◽  
Engine Development

In this paper, engine simulation tool is used to investigate the effect of variable intake manifold and variable valve timing technologies on the engine performance at full load engine conditions. Here, an engine model of 1.6 litre four cylinders, four stroke spark ignition (SI) engine is constructed using GT-Power software to represent the real engine conditions. This constructed model is then correlated to the experimental data to make sure the accuracy of this model. The comparison results of volumetric efficiency (VE), intake manifold air pressure (MAP), exhaust manifold back pressure (BckPress) and brake specific fuel consumption (BSFC) show very well agreement with the differences of less than 4%. Then this correlated model is used to predict the engine performance at various intake runner lengths (IRL) and various intake valve open (IVO) timings. Design of experiment and optimisation tool are applied to obtain optimum parameters. Here, several configurations of IRL and IVO timing are proposed to give several options during the engine development work. A significant improvement is found at configuration of variable IVO timing and variable IRL compared to fixed IVO timing and fixed IRL.

Improved throttle valve modeling for spark-ignition engine simulations

2018 ◽  
Vol 233 (6) ◽  
pp. 1614-1622 ◽  
Author(s):  
Elie Haddad ◽  
David Chalet ◽  
Pascal Chesse
Keyword(s):  
Internal Combustion Engine ◽  
Discharge Coefficient ◽  
Test Bench ◽  
Combustion Engine ◽  
Internal Combustion ◽  
Simulation Software ◽  
Spark Ignition Engine ◽  
Engine Test ◽  
Engine Simulation ◽  
Throttle Valve

Automotive manufacturers nowadays are constantly working on improving their internal combustion engines’ performance by reducing the fuel consumption and emissions, without compromising the power generated. Manufacturers are therefore relying on virtual engine models that can be run on simulation software in order to reduce the amount of time and costs needed, in comparison with experiments done on engine test benches. One important element of the intake system of an internal combustion engine is the throttle valve, which defines the amount of air reaching the plenum before being drawn into the cylinders. This article discusses a widely used model for the estimation of air flow rate through the throttle valve in an internal combustion engine simulation. Experiments have been conducted on an isolated throttle valve test bench in order to understand the influence of different factors on the model’s discharge coefficient. These experiments showed that the discharge coefficient varies with the pressure ratio across the throttle valve and with its angle. Furthermore, for each angle, this variation can be approximated with a linear model composed of two parameters: the slope and the Y-Intercept. These parameters are calibrated for different throttle valve angles. This calibration can be done using automotive manufacturers’ standard engine test fields that are often available. This model is then introduced into an engine simulation model, and the results are compared to the experimental data of a turbocharged engine test bench for validation. They are also compared with a standard discharge coefficient model that varies only with the throttle valve angle. The results show that the new model for the discharge coefficient reduces mass flow estimation errors and allows expanding the applications of the throttle valve isentropic nozzle model.

Mean Flow Measurements Near the Plane of an Open Rotor Operating with an Inlet Velocity Gradient

1981 ◽  
Vol 103 (2) ◽  
pp. 445-450
Author(s):  
M. L. Billet
Keyword(s):  
Flow Field ◽  
Velocity Profile ◽  
Velocity Gradient ◽  
Vortex Motion ◽  
Field Measurements ◽  
Velocity Data ◽  
Mean Flow ◽  
Flow Measurements ◽  
Inlet Velocity ◽  
Open Rotor

As part of a study on the structure of a trailing vortex, laser doppler anemometer (LDA) measurements were made of the flow field near an open rotor having an inlet velocity gradient. The measurements were made in the 1.22 m dia water tunnel of the Applied Research Laboratory at The Pennsylvania State University. Velocity data were obtained for rotor inlet and outlet flow fields for several different inlet velocity gradients. Velocity data were also obtained downstream of the rotor plane that shows the vortex structure. Flow field measurements show the development of the downstream vortex motion. Small variations in the inlet velocity gradient near the rotor wall caused large differences in the structure of the trailing vortex. In addition, a measured downstream velocity profile is compared with a calculated velocity profile.

Study on Optimization of the Diesel Engine Controlling Parameters Based on Genetic Algorithm

2012 ◽  
Vol 253-255 ◽  
pp. 2125-2129
Author(s):  
Qing Guo Luo ◽  
Hong Bin Liu ◽  
Qiang Ma
Keyword(s):  
Genetic Algorithm ◽  
Diesel Engine ◽  
Economic Efficiency ◽  
Test Sample ◽  
Opening Angle ◽  
Maximum Pressure ◽  
Intake Valve ◽  
Engine Simulation ◽  
Exhaust Temperature ◽  
Virtual Test

The diesel engine simulation model build by the GT-POWER software was tested and verified. The advance angle of injection, the opening angle of intake valve and the opening angle of exhaust valve was calculated to get the virtual test sample of diesel engine running under the rated condition. The optimization model was built based on the genetic algorithm, and three parameters were optimized aimed at the economic efficiency under the constraint of the maximum pressure in cylinder and the exhaust temperature; the error between the optimization and the simulation result was below 3%.

Experimental and Numerical Investigations on Basic Characteristics of High-Performance Abradable-Aero Hybrid Seal

2014 ◽  
Author(s):  
Yoshihiro Kuwamura ◽  
Kazuyuki Matsumoto ◽  
Hidekazu Uehara ◽  
Hiroharu Ooyama ◽  
Yoshinori Tanaka ◽  
...  
Keyword(s):  
Mass Flow ◽  
Vortex Structure ◽  
High Performance ◽  
Discharge Coefficient ◽  
Labyrinth Seal ◽  
Axial Position ◽  
Leakage Flow ◽  
Flow Measurements ◽  
Wide Range ◽  
Basic Characteristics

As key technologies to improve the performance of steam turbines, various types of high performance seal, such as active clearance control (ACC) seals and leaf seals [1], have been developed by Mitsubishi Heavy Industries, LTD (MHI). In recent years, a new seal concept using an aerodynamic approach called “aero seal” has also been developed, which remarkably reduces the leakage flow while maintaining fin clearances. Furthermore, more robust and higher performance sealing technology called “abradable-aero hybrid seal” which combines the aero seal concept with the abradable seal technology was proposed. The main concept of the aero seal is to control and utilize the vortex structure in the cavities of the labyrinth seal. In the cavities of the aero seal, the locally-controlled flow on the upstream side of the fin tip causes a strong contraction of the leakage flow and reduces the discharge coefficient significantly. This concept allows for a remarkably reduced leakage flow while maintaining fin clearances. Moreover, in order to achieve more robust and higher performance by minimizing the fin clearances, the abradable seal technology was applied to the aero seal concept. However, when the abradable seal is applied, the grooves may be formed on the wall surface of the abradable material due to rubbing of the fin into the abradable material. This situation leads to concern that the groove breaks the effective vortex structure of aero seal and causes negative effects on the seal performance. In this paper, the improved aero seal configuration consisting of slant fins was proposed and it was verified that the reduction in the discharge coefficient of improved aero seal is up to 40% compared to the conventional labyrinth seal. Furthermore, more robust and higher performance sealing technology called “abradable-aero hybrid seal” was proposed and basic characteristics such as the effects of the presence of grooves, the axial position of the fin and seal clearance on the leakage mass flow and the vortex structure were parametrically investigated both experimentally and numerically. In the experiments, not only leakage mass flow measurements but also PIV measurements were carried out in order to visualize the flow patterns in the cavity of the abradable-aero hybrid seal. From the results, it was confirmed that the effective vortex structures were formed even with grooves at various fin positions and the leakage flow can be stably reduced over 40% in a wide range of axial position and reduced by 50% at the optimum position.

Flow Characteristics of Long Orifices With Rotation and Corner Radiusing

1988 ◽  
Vol 110 (2) ◽  
pp. 213-217 ◽  
Author(s):  
W. F. McGreehan ◽  
M. J. Schotsch
Keyword(s):  
Reynolds Number ◽  
Test Data ◽  
Discharge Coefficient ◽  
Flow Characteristics ◽  
Arbitrary Geometry ◽  
Inlet Velocity ◽  
Corner Radius ◽  
Flow Effects

The discharge coefficient of an orifice is a function of both geometric and flow effects, such as inlet corner radius, orifice length, inlet velocity orientation, and Reynolds number. Loss characteristics are available for each of these effects; however, a need exists for a reasonable method of predicting the discharge coefficient with an arbitrary combination of the above effects. Presented is a technique for calculating the discharge coefficient for arbitrary geometry with results compared to test data.

scholarly journals Discharge Coefficient of Poppet Intake Valve with Rotating Flow.

1994 ◽  
Vol 60 (572) ◽  
pp. 1463-1469
Author(s):  
Seiichi Tanabe ◽  
Guo Bang Liu ◽  
Yukio Kashiwada ◽  
Ryouji Waka
Keyword(s):  
Discharge Coefficient ◽  
Rotating Flow ◽  
Intake Valve

Numerical Study of Inlet and Geometry Effects on Discharge Coefficients for Liquid Jet Emanating From a Plain-Orifice Atomizer

2002 ◽  
Vol 18 (3) ◽  
pp. 153-161 ◽  
Author(s):  
Chun-Lang Yeh
Keyword(s):  
Reynolds Number ◽  
Turbulence Intensity ◽  
Discharge Coefficient ◽  
Numerical Study ◽  
Surface Force ◽  
Diameter Ratio ◽  
The Body ◽  
Liquid Jet ◽  
Discharge Coefficients ◽  
Geometry Effects

AbstractA computational model for flow in a plain-orifice atomizer is established to examine the inlet and geometry effects on discharge coefficients. The volume of fluid (VOF) method with finite volume formulation was employed to capture the liquid/gas interface. A continuum Surface Force (CSF) model was adopted to model the surface tension. The body-fitted coordinate system was used to facilitate the configuration of the atomizer. The influences of the inlet chamfer angle, the orifice length/diameter ratio, the Reynolds number, and the inlet turbulence intensity are analyzed. It is found that the optimum discharge coefficient occurs at a chamfer angle of about 50°. The discharge coefficient at first increases with the increase in the orifice length/diameter ratio and then it decreases. The discharge coefficient increases with the increase in the Reynolds number up to Re = 40000, after which it remains sensibly constant. The influence of the inlet turbulence intensity on discharge coefficient is not significant, especially for a longer orifice.

scholarly journals Flow Transition Phenomena and Heat Transfer Over the Pressure Surfaces of Gas Turbine Blades

1981 ◽  
Author(s):  
A. Brown ◽  
B. W. Martin
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Turbulence Intensity ◽  
Aerodynamic Drag ◽  
Turbine Blades ◽  
Detailed Examination ◽  
Design Criterion ◽  
Flow Transition ◽  
Flow Measurements ◽  
Gas Turbine Blades

Detailed examination of flow measurements over concave pressure surfaces suggests that interaction of Taylor-Goertler vorticity with mainstream turbulent exerts only limited influence in enhancing laminar boundary-layer heat transfer. While transition is primarily controlled by the Launder laminarisation criterion, the Goertler number at which it subsequently occurs is not solely determined by turbulence intensity. Adoption of K >2.5.10 ± as a design criterion for the pressure surfaces of turbine blades would appear to have significant advantages in terms of reduced heat transfer, increased lift, and lower aerodynamic drag.

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