Experimental and numerical analysis of the multiphase flow distribution in multi plate wetclutches for HVT transmissions under actual operating conditions

2018 ◽  
Author(s):  
Stefano Terzi ◽  
Massimo Milani ◽  
Luca Montorsi ◽  
Bernhard Manhartsgruber
Keyword(s):  
Numerical Analysis ◽  
Multiphase Flow ◽  
Flow Distribution ◽  
Operating Conditions ◽  
Actual Operating

A Combined 0D-3D Numerical Approach for the Performance Prediction of Vehicles’ Heat Exchangers Under Actual Operating Conditions

2017 ◽  
Author(s):  
Luca Montorsi ◽  
Massimo Martelli ◽  
Silvia Gessi ◽  
Massimo Milani
Keyword(s):  
Heat Exchanger ◽  
Heat Exchangers ◽  
Fluid Velocity ◽  
Flow Characteristics ◽  
Flow Distribution ◽  
Numerical Approach ◽  
Operating Conditions ◽  
Internal Boundary ◽  
Actual Operating ◽  
Custom Made

The paper focuses on the development of a predictive numerical tool for the performance assessment of air-cooled cross-flow heat exchangers for vehicle application. First, a CFD approach for the simulation of vehicles’ radiators under actual operating conditions is proposed. The numerical analysis accounts both for the thermo-fluid dynamics behavior of each section of the heat exchanger and for the flow characteristics of the adopted fan. The full-scale geometry of the fan is included in the simulation as well as the casing and the real rotational speed. The CFD results are used to correlate the flow distribution across the different radiator’s sections and the actual working conditions of both the heat exchanger and the fan operation. Following this methodology, a generic radiator was divided in two different sub-domain types (internal/boundary), and for each one the Wall Heat Transfer Coefficient and the pressure drop 2D maps are determined on the basis of preliminary CFD simulations as functions of fluid velocity and temperature. These elements became the elementary blocks to be used by a custom-made algorithm to characterize exchangers of any size. The algorithm was extended to develop a fully featured PC software to calculate the performance of multiple sections exchangers.

Experimental and numerical analysis to identify the performance limiting mechanisms in solid-state lithium cells under pulse operating conditions

2019 ◽  
Vol 21 (41) ◽  
pp. 22740-22755 ◽  
Author(s):  
Mei-Chin Pang ◽  
Yucang Hao ◽  
Monica Marinescu ◽  
Huizhi Wang ◽  
Mu Chen ◽  
...  
Keyword(s):  
Solid State ◽  
Numerical Analysis ◽  
Energy Density ◽  
Lithium Ion Batteries ◽  
Lithium Batteries ◽  
Safety Concern ◽  
Lithium Ion ◽  
Thermal Runaway ◽  
Operating Conditions ◽  
Lithium Cells

Solid-state lithium batteries could reduce the safety concern due to thermal runaway while improving the gravimetric and volumetric energy density beyond the existing practical limits of lithium-ion batteries.

Numerical simulation and experimental performance research of cylindrical vane pump

2021 ◽  
pp. 095440622110200
Author(s):  
Yiqi Cheng ◽  
Xinhua Wang ◽  
Waheed Ur Rehman ◽  
Tao Sun ◽  
Hasan Shahzad ◽  
...  
Keyword(s):  
Numerical Analysis ◽  
Rotational Velocity ◽  
Geometric Theory ◽  
Mechanical Efficiency ◽  
Operating Conditions ◽  
Experimental Results ◽  
Field Analysis ◽  
Total Efficiency ◽  
Three Dimensional Model ◽  
Vane Pump

This study presents a novel cylindrical vane pump based on the traditional working principle. The efficiency of the cylindrical vane pump was verified by experimental validation and numerical analysis. Numerical analysis, such as kinematics analysis, was performed in Pro/Mechanism and unsteady flow-field analysis was performed using ANSYS FLUENT. The stator surface equations were derived using the geometric theory of the applied spatial triangulation function. A three-dimensional model of the cylindrical vane pump was established with the help of MATLAB and Pro/E. The kinematic analysis helped in developing kinematic equations for cylindrical vane pumps and proved the effectiveness of the structural design. The maximum inaccuracy error of the computational fluid dynamics (CFD) model was 5.7% compared with the experimental results, and the CFD results show that the structure of the pump was reasonable. An experimental test bench was developed, and the results were in excellent agreement with the numerical results of CFD. The experimental results show that the cylindrical vane pump satisfied the three-element design of a positive-displacement pump and the trend of changes in efficiency was the same for all types of efficiency under different operating conditions. Furthermore, the volumetric efficiency presented a nonlinear positive correlation with increased rotational velocity, the mechanical efficiency showed a nonlinear negative correlation, and the total efficiency first increased and then decreased. When the rotational velocity was 1.33[Formula: see text] and the discharge pressure was 0.68[Formula: see text], the total efficiency reached its maximum value.

Numerical Analysis of the Heat and Mass Transfer Characteristics in an Autothermal Methane Reformer

2010 ◽  
Vol 7 (5) ◽  
Author(s):  
Joonguen Park ◽  
Shinku Lee ◽  
Sunyoung Kim ◽  
Joongmyeon Bae
Keyword(s):  
Mass Transfer ◽  
Numerical Analysis ◽  
Heat And Mass Transfer ◽  
Steam Reforming ◽  
Space Velocity ◽  
Reaction Model ◽  
Operating Conditions ◽  
Local Thermal Equilibrium ◽  
Inlet Temperature ◽  
Transfer Characteristics

This paper discusses a numerical analysis of the heat and mass transfer characteristics in an autothermal methane reformer. Assuming local thermal equilibrium between the bulk gas and the surface of the catalyst, a one-medium approach for the porous medium analysis was incorporated. Also, the mass transfer between the bulk gas and the catalyst’s surface was neglected due to the relatively low gas velocity. For the catalytic surface reaction, the Langmuir–Hinshelwood model was incorporated in which methane (CH4) is reformed to hydrogen-rich gases by the autothermal reforming (ATR) reaction. Full combustion, steam reforming, water-gas shift, and direct steam reforming reactions were included in the chemical reaction model. Mass, momentum, energy, and species balance equations were simultaneously calculated with the chemical reactions for the multiphysics analysis. By varying the four operating conditions (inlet temperature, oxygen to carbon ratio (OCR), steam to carbon ratio, and gas hourly space velocity (GHSV)), the performance of the ATR reactor was estimated by the numerical calculations. The SR reaction rate was improved by an increased inlet temperature. The reforming efficiency and the fuel conversion reached their maximum values at an OCR of 0.7. When the GHSV was increased, the reforming efficiency increased but the large pressure drop may decrease the system efficiency. From these results, we can estimate the optimal operating conditions for the production of large amounts of hydrogen from methane.

Numerical analysis of flow distribution for combined weapon system in environmental tester

2012 ◽  
Vol 26 (10) ◽  
pp. 3339-3345 ◽  
Author(s):  
Sung-Dae Kim ◽  
Sang-Hwa Baek ◽  
Tae-Yeob Kang ◽  
So-Jin Park ◽  
Chulju Kim ◽  
...  
Keyword(s):  
Numerical Analysis ◽  
Flow Distribution ◽  
Weapon System

THE VALUE OF FINE BUBBLE DIFFUSER TESTING UNDER ACTUAL OPERATING CONDITIONS IN A HIGHLY INDUSTRIAL WASTEWATER

2005 ◽  
Vol 2005 (14) ◽  
pp. 2232-2247
Author(s):  
Michael S. Demko ◽  
Frank Coughenour ◽  
John J. Pacifici ◽  
Sam Jeyanayagam ◽  
David T. Redmon
Keyword(s):  
Industrial Wastewater ◽  
Operating Conditions ◽  
Actual Operating ◽  
Fine Bubble

Numerical Analysis of Non-Radial Blading in a Low Speed and Low Pressure Turbine for Electric Turbocompounding Applications

2021 ◽  
Author(s):  
Eva Alvarez-Regueiro ◽  
Esperanza Barrera-Medrano ◽  
Ricardo Martinez-Botas ◽  
Srithar Rajoo
Keyword(s):  
Numerical Analysis ◽  
Numerical Simulations ◽  
Thermal Stresses ◽  
Waste Heat ◽  
Pressure Ratio ◽  
Low Pressure ◽  
Turbine Rotor ◽  
Operating Conditions ◽  
Blade Angle ◽  
Low Speed

Abstract This paper presents a CFD-based numerical analysis on the potential benefits of non-radial blading turbine for low speed-low pressure applications. Electric turbocompounding is a waste heat recovery technology consisting of a turbine coupled to a generator that transforms the energy left over in the engine exhaust gases, which is typically found at low pressure, into electricity. Turbines designed to operate at low specific speed are ideal for these applications since the peak efficiency occurs at lower pressure ratios than conventional high speed turbines. The baseline design consisted of a vaneless radial fibre turbine, operating at 1.2 pressure ratio and 28,000rpm. Experimental low temperature tests were carried out with the baseline radial blading turbine at nominal, lower and higher pressure ratio operating conditions to validate numerical simulations. The baseline turbine incidence angle effect was studied and positive inlet blade angle impact was assessed in the current paper. Four different turbine rotor designs of 20, 30, 40 and 50° of positive inlet blade angle are presented, with the aim to reduce the losses associated to positive incidence, specially at midspan. The volute domain was included in all CFD calculations to take into account the volute-rotor interactions. The results obtained from numerical simulations of the modified designs were compared with those from the baseline turbine rotor at design and off-design conditions. Total-to-static efficiency improved in all the non-radial blading designs at all operating points considered, by maximum of 1.5% at design conditions and 5% at off-design conditions, particularly at low pressure ratio. As non-radial fibre blading may be susceptible to high centrifugal and thermal stresses, a structural analysis was performed to assess the feasibility of each design. Most of non-radial blading designs showed acceptable levels of stress and deformation.

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