Evaluation of the Effect of the Working Fluid Density on the Characteristics of the Torque Converter

2021 ◽  
Author(s):  
G. S. Mazlumyan ◽  
S. A. Eruslankin ◽  
R. V. Yushchuk
Keyword(s):  
Torque Converter ◽  
Working Fluid ◽  
Fluid Density

Experimental Investigation on Cavitation Performance of Torque Converter Using Transparent Model

2019 ◽  
Author(s):  
Yusuke Katayama ◽  
Yuki Hosoi ◽  
Yuta Fukuda ◽  
Satoshi Watanabe ◽  
Shin-ichi Tsuda ◽  
...  
Keyword(s):  
High Speed ◽  
Turbine Blades ◽  
Suction Side ◽  
Torque Converter ◽  
Working Fluid ◽  
Speed Ratio ◽  
Cavitation Phenomenon ◽  
Cavitation Bubbles ◽  
Charge Pressure ◽  
Dissolved Air

Abstract In this study, we experimentally investigated the influence of the amount of dissolved air in working fluid and the rotation speed ratio of turbine to pump elements on cavitation phenomenon in automotive torque converter. In order to directly observe the cavitation phenomenon, transparent model was used. The applied charge pressure was varied to change the significance of cavitation. The pump and turbine torques were simultaneously measured to clarify the relation between torque performance and cavitation phenomenon. As a result, the cavitation region was found to depend on the speed ratio; cavitation occurred on the suction side of turbine blades at low speed ratios while in the pump region at high speed ratios. The effect of the amount of dissolved air was significant, which enhanced the growth of cavitation bubbles through the deposition of dissolved air. In such cases, with the further decrease of charge pressure, a large number of gaseous cavitation bubbles appeared in the whole flow passage. The torque performance was deteriorated at this stage.

scholarly journals Laser Velocimeter Measurements in the Pump of an Automotive Torque Converter Part II – Effect of Pump Speed and Oil Viscosity

2000 ◽  
Vol 6 (3) ◽  
pp. 181-190 ◽  
Author(s):  
Ronald D. Flack ◽  
Steven B. Ainley ◽  
Klaus Brun ◽  
Leonard Whitehead
Keyword(s):  
Rotational Speed ◽  
Three Dimensional ◽  
Torque Converter ◽  
Secondary Flows ◽  
Working Fluid ◽  
Speed Ratio ◽  
Oil Viscosity ◽  
Low Velocity ◽  
Pump Speed ◽  
Mass Flows

The velocity field inside a torque converter pump was studied for two separate effects: variable pump rotational speed and variable oil viscosity. Three-dimensional velocity measurements were taken using a laser velocimeter for both the pump mid- and exit planes. The effect ofvariable pump rotational speed was studied by running the pump at two different speeds and holding speed ratio (pump rotational speed]turbine rotational speed) constant. Similarly, the effect of viscosity on the pump flow field was studied by varying the temperature and]or using two different viscosity oils as the working fluid in the pump. Threedimensional velocity vector plots, through-flow contour plots, and secondary flow profiles were obtained for both pump planes and all test conditions. Results showed that torque converter mass flows increased approximately linearly with increasing pump rotational speed (and fixed speed ratio) but that the flow was not directly proportional to pump rotational speed. However, mass flows were seen to decrease as the oil viscosity was decreased with a resulting increased Reynolds number; for these conditions the high velocity regions were seen to decrease in size and low velocity regions were seen to increase in size. In the pump mid-plane strong counter-clockwise secondary flows and in the exit plane strong clockwise secondary flows were observed. The vorticities and slip factors were calculated from the experimental results and are presented. The torque core-to-shell and blade-to-blade torque distributions were calculated for both planes. Finally, the flow fields were seen to demonstrate similitude when Reynolds numbers were matched.

Effects of Number of Stator Blades on the Performance of a Torque Converter

2011 ◽  
Author(s):  
Shoab Ahmed Talukder ◽  
B. Phuoc Huynh
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Software Package ◽  
Torque Converter ◽  
Working Fluid ◽  
Speed Ratio ◽  
Industrial Oil ◽  
Transmission Shaft ◽  
Computational Fluid Dynamics Cfd ◽  
Speed Change

Torque converter (TC) is a totally enclosed hydrodynamic turbomachine, used most often in automobiles for the smooth transfer of power and speed change from the engine to the transmission, and torque magnification. A typical TC has 3 major components: a pump that is attached directly to the TC cover and connected to the engine shaft, a turbine connected to the transmission shaft, and a stator connected to the transmission housing via a one-way clutch and providing guidance for the fluid flow. In this work, effects of the number of stator blades on the performance of a TC are investigated numerically, using a commercial Computational Fluid Dynamics (CFD) software package. The standard k-epsilon turbulence model was used. A Newtonian fluid whose properties correspond to industrial oil was used for the working fluid. The range of speed ratio (between turbine’s speed and pump’s) of 0.2–0.8 was considered. It was found that as the stator blades’ number increases (here from 13 to 19), the TC’s efficiency and torque ratio vary significantly, passing through minimum and generally also reaching a maximum.

Understanding frequency response of thermal micropumps using electrical network analogy

2014 ◽  
Vol 92 (10) ◽  
pp. 1178-1184
Author(s):  
Hamzeh. K. Bardaweel
Keyword(s):  
Frequency Response ◽  
Transfer Functions ◽  
Model Simulation ◽  
Electrical Network ◽  
Working Fluid ◽  
Fluid Density ◽  
Equivalent Network ◽  
Flow Rates ◽  
Model Simulations ◽  
Stiffness And Damping

In this article the frequency response of a thermal micropump is investigated using electrical network analogy modeling technique. This technique is based on dividing the micropump into subsystems and representing each subsystem using the equivalent network analogy. Obtained mathematical models of subsystems are then represented using transfer functions and block diagrams. As an example, thermopneumatic micropump is considered. Model simulation suggests an increase in the net flow rates of the micropump as the operating frequencies increased, until a first cut-off frequency is reached. A second cut-off frequency is observed with further increase in operating frequencies. Model simulations are consistent with qualitative experimental trends reported in the literature. The model is used to obtain a relationship between cut-off frequencies and design properties of the micropump. Model simulations show that lower cut-off frequency is related to mechanical properties of the thermopneumatic micropump, including stiffness and damping. Upper cut-off frequency is related to thermal properties of the thermopneumatic micropump, including thermal conductivity, heat capacity, and working fluid density.

Aerodynamic Torque Converter for Gas Turbines

1969 ◽  
Author(s):  
Charles C. Hill
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Thermodynamic Characteristics ◽  
Torque Converter ◽  
Working Fluid ◽  
Hydraulic Torque Converter ◽  
Gas Turbine Cycle ◽  
Aerodynamic Torque ◽  
Operational Aspects

A new concept in transmissions for gas turbines, called an Aerodynamic Torque Converter, is proposed. The ATC is similar to a hydraulic torque converter but uses a compressible working fluid which results in several unique characteristics when combined with a gas turbine cycle. Control and operational aspects of the ATC are discussed and equations showing its basic thermodynamic characteristics are developed.

scholarly journals Predicting the Onset of Cavitation in Automotive Torque Converters—Part I: Designs with Geometric Similitude

2008 ◽  
Vol 2008 ◽  
pp. 1-8 ◽  
Author(s):  
D. L. Robinette ◽  
J. M. Schweitzer ◽  
D. G. Maddock ◽  
C. L. Anderson ◽  
J. R. Blough ◽  
...  
Keyword(s):  
Dimensional Analysis ◽  
Scaling Law ◽  
Torque Converter ◽  
Working Fluid ◽  
Product Model ◽  
Geometric Scaling ◽  
Fluid Properties ◽  
Torque Converters ◽  
Operating Points ◽  
Onset Of Cavitation

Dimensional analysis has been applied to automotive torque converters to understand the response of performance to changes in torque, size, working fluid, or operating temperature. The objective of this investigation was to develop a suitable dimensional analysis for estimating the effect of exact geometric scaling of a particular torque converter design on the onset of cavitation. Torque converter operating thresholds for cavitation were determined experimentally with a dynamometer test cell at the stall operating condition using nearfield acoustical measurements. Dimensionless quantities based upon either speed or torque at the onset of cavitation and flow properties (e.g., pressures and temperature dependent fluid properties) were developed and compared. The proposed dimensionless stator torque quantity was found to be the most appropriate scaling law for extrapolating cavitation thresholds to multiple diameters. A power product model was fit on dimensionless stator torque data to create a model capable of predicting cavitation thresholds. Comparison of the model to test data taken over a range of operating points showed an error of 3.7%. This is the first paper of a two-part paper. In Part II, application of dimensional analysis will be expanded from torque converters with exact geometric similitude to those of more general design.

Experimental study of thermohydraulic characteristics and irreversibility analysis of novel axial corrugated tube with spring tape inserts

2020 ◽  
Vol 92 (3) ◽  
pp. 30901
Author(s):  
Suvanjan Bhattacharyya ◽  
Debraj Sarkar ◽  
Ulavathi Shettar Mahabaleshwar ◽  
Manoj K. Soni ◽  
M. Mohanraj
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Thermal Performance ◽  
Working Fluid ◽  
The Novel ◽  
Heat Exchanger Tube ◽  
Heat Transfer Augmentation ◽  
Corrugated Tube ◽  
The Impact ◽  
Exchanger Tube

The current study experimentally investigates the heat transfer augmentation on the novel axial corrugated heat exchanger tube in which the spring tape is introduced. Air (Pr = 0.707) is used as a working fluid. In order to augment the thermohydraulic performance, a corrugated tube with inserts is offered. The experimental study is further extended by varying the important parameters like spring ratio (y = 1.5, 2.0, 2.5) and Reynolds number (Re = 10 000–52 000). The angular pitch between the two neighboring corrugations and the angle of the corrugation is kept constant through the experiments at β = 1200 and α = 600 respectively, while two different corrugations heights (h) are analyzed. While increasing the corrugation height and decreasing the spring ratio, the impact of the swirling effect improves the thermal performance of the system. The maximum thermal performance is obtained when the corrugation height is h = 0.2 and spring ratio y = 1.5. Eventually, correlations for predicting friction factor (f) and Nusselt number (Nu) are developed.

Model, simulation and experiments for a Buoyancy Organic Rankine Cycle

2020 ◽  
Vol 92 (1) ◽  
pp. 10906
Author(s):  
Jeroen Schoenmaker ◽  
Pâmella Gonçalves Martins ◽  
Guilherme Corsi Miranda da Silva ◽  
Julio Carlos Teixeira
Keyword(s):  
Model Simulation ◽  
Organic Rankine Cycle ◽  
Thermodynamic Cycle ◽  
Rankine Cycle ◽  
Test Body ◽  
Working Fluid ◽  
Proof Of Concept ◽  
Energy Scenario ◽  
New Type ◽  
Fluid Reservoir

Organic Rankine Cycle (ORC) systems are increasingly gaining relevance in the renewable and sustainable energy scenario. Recently our research group published a manuscript identifying a new type of thermodynamic cycle entitled Buoyancy Organic Rankine Cycle (BORC) [J. Schoenmaker, J.F.Q. Rey, K.R. Pirota, Renew. Energy 36, 999 (2011)]. In this work we present two main contributions. First, we propose a refined thermodynamic model for BORC systems accounting for the specific heat of the working fluid. Considering the refined model, the efficiencies for Pentane and Dichloromethane at temperatures up to 100 °C were estimated to be 17.2%. Second, we show a proof of concept BORC system using a 3 m tall, 0.062 m diameter polycarbonate tube as a column-fluid reservoir. We used water as a column fluid. The thermal stability and uniformity throughout the tube has been carefully simulated and verified experimentally. After the thermal parameters of the water column have been fully characterized, we developed a test body to allow an adequate assessment of the BORC-system's efficiency. We obtained 0.84% efficiency for 43.8 °C working temperature. This corresponds to 35% of the Carnot efficiency calculated for the same temperature difference. Limitations of the model and the apparatus are put into perspective, pointing directions for further developments of BORC systems.

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