Flow Field Analysis Around a Lockup Clutch Inside a Torque Converter

2011 ◽  
Author(s):  
Takeshi Yamaguchi ◽  
Shogo Ikeda ◽  
Sho Yamakawa ◽  
Kazuhiro Tanaka
Keyword(s):  
Steady State ◽  
Flow Field ◽  
Automatic Transmission ◽  
Steady State Solution ◽  
Torque Converter ◽  
Field Analysis ◽  
Hydrodynamic Performance ◽  
Transient Solution ◽  
Good Opportunity ◽  
Clutch Engagement

The performance of a torque converter has been one of the most important areas of improvement for an automatic-transmission equipped automobile. Improving the torque converter’s performance and efficiency is key to saving fuel consumption, which is an important consideration with recent environmental awareness. Moreover, the locking up operation or slipping control of an automatic transmission is another good opportunity for improving fuel economy. For this reason, there has been much research carried out to predict hydrodynamic performance and to understand the flow field inside a torque converter either experimentally or analytically using Computational Fluid Dynamics (CFD). Most of the research to date has focused on the inside of a torque converter torus. In recent years, the usage of a lockup clutch has expanded, and the lockup control system has become more complex. Understanding the flow field around the lockup clutch has become a very important issue. Only a few studies have focused on the lockup clutch, and most of the numerical research was solved at steady state conditions. In this paper, not only was an unsteady solution applied to solve the flow field, but also two new techniques were attempted. One was “virtual weight” and the other was “moving mesh.” By using these techniques, the lockup clutch was moved by the balance of its own weight and the opposing pressure acting on its surface. With this approach, the lockup clutch engagement time or the responsiveness of the lockup clutch could be estimated. The flow field calculated by a transient solution was found to be different from the flow field calculated by a steady state solution. The transient solution also revealed that the lockup engagement time and the lockup clutch moving speed were dependent on the lockup engagement pressure and rotation speed.

Flow Field Analysis Around the Ship Fin Stabilizer Including Free Surface

2009 ◽  
Author(s):  
Fatemah Hoseini Dadmarzi ◽  
Hassan Ghassemi ◽  
Parviz Ghadimi ◽  
Babak Ommani
Keyword(s):  
Free Surface ◽  
Flow Field ◽  
Numerical Data ◽  
Numerical Results ◽  
Field Analysis ◽  
Hydrodynamic Performance ◽  
Pressure Distributions ◽  
Flow Field Analysis ◽  
Ship Roll ◽  
Fin Stabilizer

Fin stabilizers are very important device for controlling the ship roll motion against the external moments due to wave. This paper presents numerical results for flow field simulation and the hydrodynamic performance of fin stabilizer attached to a ship hull with free surface effects. Combination of CFD and RANS method has been used for this study. The fin is non-rectangular NACA0015 profile section with a finite aspect ratio. The numerical results include pressure distributions and flow field around the fin which are used to calculate lift coefficients and free surface elevation as the main interest. Some results are compared with available experimental and numerical data in literature and they show good agreement.

Comparison of Transient and Steady-State Behaviors in Unwinding Mechanism

2011 ◽  
Author(s):  
Wan-Suk Yoo ◽  
Kun-Woo Kim ◽  
Deuk-Man An ◽  
Jae-Wook Lee
Keyword(s):  
Steady State ◽  
Tensile Force ◽  
Equations Of Motion ◽  
Finite Difference Methods ◽  
Nonlinear Partial Differential Equations ◽  
Inertial Force ◽  
Steady State Solution ◽  
State Solution ◽  
Resistance Force ◽  
Transient Solution

In this study, the transient analysis of a cable unwinding from a cylindrical spool package is first studied and compared to experiment. Then, a steady-state solution is also compared to transient solution. Cables are assumed to be withdrawn with a constant velocity through a fixed point which is located along the axis of the package. When the cable is flown out of the package, several dynamic forces, such as inertial force, Coriolis force, centrifugal force, tensile force, and fluid-resistance force are acting on the cable. Consequently, the cable becomes to undergo very nonlinear and complex unwinding behavior which is called unwinding balloon. In this paper, to prevent the problems during unwinding such as tangling or cutting, unwinding behaviors of cables in transient state were derived and analyzed. First of all, the governing equations of motion of cables unwinding from a cylindrical spool package were systematically derived using the extended Hamilton’s principles of an open system in which mass is transported at each boundary. And the modified finite difference methods are suggested to solve the derived nonlinear partial differential equations. Time responses of unwinding cables are calculated using Newmark time integration methods. The transient solution is compared to physical experiment, and then the steady-state solution is compared to transient solution.

Research on Numerical Investigation and Test Verification of Brake Performance in a Hydrodynamic Tractor-Retarder Assembly

2010 ◽  
Vol 97-101 ◽  
pp. 3357-3361
Author(s):  
Wei Wei ◽  
Qing Dong Yan ◽  
Jing Yan Wu
Keyword(s):  
Experimental Data ◽  
Flow Field ◽  
Internal Flow ◽  
Torque Converter ◽  
Field Analysis ◽  
Rotating Speed ◽  
Spiral Vortex ◽  
Work Mechanism ◽  
Flow Field Analysis ◽  
Brake Performance

The brake performance of a hydrodynamic tractor-retarder assembly, which is the combination of torque converter and hyaulic retarder, was studied to explore its work mechanism. Spiral vortex distribution pattern of internal flow field in the assembly was discovered on the basis of reasonable boundary condition, where runaway speed of stator was determined by CFD analysis. Comparison of experimental data and flow field analysis shows that accurate brake performance of hydrodynamic tractor-retarder assembly can be calculated only by 3D flow field analysis presently and numerical simulation results is close to experimental data, and approximate linear relationship exists between runaway speed of stator and rotating speed of pump.

Diffusion coefficient calculated by time-lag using the film-roll method

2021 ◽  
pp. 004051752110278
Author(s):  
Geon Yong Park
Keyword(s):  
Diffusion Coefficient ◽  
Steady State ◽  
Boundary Conditions ◽  
Arrhenius Plot ◽  
Regression Line ◽  
Time Lag ◽  
Steady State Solution ◽  
Transient Solution ◽  
Steady State Condition ◽  
State Concentration

A method for determining the diffusion coefficient by time-lag using the film-roll method for the sublimation diffusion of disperse dye was proposed. A polyethylene terephthalate film-roll coated with dye paste was treated at 170–190°C for various times. A solution consisting of the sum of a steady-state solution and a transient solution was obtained by the homogeneous boundary value problem from a trigonometrical series. The boundary conditions of the steady-state first layer and the steady-state first layer amount of dye were determined from the steady-state concentration distribution. For various diffusion times, the steady-state first layer-passed total amounts of dye that passed through the first layer in the steady-state condition were obtained by subtracting the steady-state first layer amounts from the total amounts. The time-lag was calculated from the linear regression line for the plot of the steady-state first layer-passed total number(X) of positive values against time. The diffusion coefficient was calculated by the boundary conditions of the steady-state first layer and the time-lag. For diffusion at 170°C, 180°C, and 190°C, the correlations of the steady-state first layer-passed total amounts with respect to time were very linear and the reliability of the diffusion coefficients obtained by the time-lag was proved by the good linearity of the Arrhenius plot. The activation energy obtained was 36.8 kcal[Formula: see text]mol−1.

scholarly journals M[x]/G/1 Multistage Queue with Stand-by Server During Main Server’s Interruptions

2018 ◽  
Vol 11 (1) ◽  
pp. 275 ◽  
Author(s):  
Yuvarani Chandrasekaran ◽  
Vijayalakshmi C
Keyword(s):  
Steady State ◽  
Delay Time ◽  
Steady State Solution ◽  
Single Server ◽  
Supplementary Variable ◽  
Transient Solution ◽  
Variable Technique ◽  
Multiple Vacation ◽  
Server Breakdown ◽  
Two Phases

<p>This paper investigates a multistage batch arrival queue with different server interruptions and a second server replaces the main server during the interruptions. The different server interruptions are assumed to be: multiple vacation, extended vacation, breakdown with delay time and server under two phases of repair. Customers are assumed to arrive in batches according to Poisson process and a single server provides service to the customers. When the main server is inactive due to the interruptions, stand-by server provide service to the arrivals. In addition, customers may renege during server breakdown or during server vacation due to impatience. Transient solution and the corresponding steady state solution is derived using supplementary variable technique.</p>

Effects of suction-injection-combination (SIC) on transient free-convective-radiative flow in a vertical porous channel

2016 ◽  
Vol 231 (2) ◽  
pp. 73-82
Author(s):  
Basant Kumar Jha ◽  
Chibuike Iro ◽  
Sylvester Bakut Joseph
Keyword(s):  
Steady State ◽  
Convective Flow ◽  
Steady State Solution ◽  
Working Fluid ◽  
Value Of Time ◽  
Physical Situation ◽  
Transient Solution ◽  
Free Convective Flow ◽  
Implicit Finite Difference ◽  
Time Required

The effect of suction/injection on transient free-convective flow bounded by two infinite vertical parallel porous plates in the presence of thermal radiation is investigated numerically as well as analytically. The transient mathematical model has been solved using the implicit finite difference method while the steady state version of the physical situation has been solved using perturbation method. During the course of numerical computation, an excellent agreement was found between transient solution at large value of time and steady state solution. In addition, it was found that the time required to reach steady state is directly proportional to the Prandtl number of the working fluid for fixed values of other controlling parameters.

Torque Converter Stress Analysis by Transient FSI Technique

2011 ◽  
Author(s):  
Takeshi Yamaguchi ◽  
Akihiko Okumura
Keyword(s):  
Automatic Transmission ◽  
Deformation Mode ◽  
Torque Converter ◽  
Previous Method ◽  
Hydrodynamic Performance ◽  
Element Analysis ◽  
Engine Torque ◽  
The Core ◽  
Computational Fluid Dynamics Cfd ◽  
Blade Model

The performance of a torque converter has been one of the most important areas of improvement for an automatic-transmission equipped automobile. Improving the torque converter’s performance and efficiency is key to saving fuel consumption, which is an important consideration with recent environmental awareness. Moreover, improving the overall automobile performance has led to more compact and lightweight transmissions. With the growing space constraints, the evolution of the torque converter has been towards smaller and more elliptical shapes. Since the smaller blades within the torque converter still have to endure the same engine torque, more strength is required of each blade of the pump, the turbine and the stator. There has been much research carried out to predict hydrodynamic performance and to understand the flow field inside a torque converter either experimentally or analytically using Computational Fluid Dynamics (CFD). However, none of the research has focused on the strength of the torque converter components — the blade, the shell and the core. The previous method for evaluating the blade strength had been to apply a simple, centrifugal pressure load on the blade using Finite Element Analysis (FEA). This method is no longer adequate for predicting blade stress since the pressure distribution on the blade is now known from CFD results. In this work, the fluid-structure interaction (FSI) technique is used to determine the deformation, which is indicative of the stress level of the blade, the shell and the core. In addition, this research compares the computational results from a model containing all blades to a conventional model of a single blade with axial symmetry. Analysis of the model containing all blades shows a completely different deformation mode than the single-blade model, especially for the pump blade. The differing results suggest that using a single-blade model analysis is less accurate for examining the torque converter structure.

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