Modeling of heat transfer for a wet multi-plate clutch based on empirical data

2017 ◽  
Vol 232 (12) ◽  
pp. 1634-1647
Author(s):  
SC Kim ◽  
SB Shim
Keyword(s):  
Heat Transfer ◽  
Empirical Data ◽  
System Analysis ◽  
Experimental Results ◽  
Design Parameters ◽  
Percentage Error ◽  
Inlet Temperature ◽  
Transfer Model ◽  
Validation Parameters ◽  
Wet Clutch

A heat transfer model of a wet multi-plate clutch based on empirical data is presented in this paper. Lumped system analysis was used to simplify the complex heat transfer system of the wet clutch. The model has included the effects of various design parameters of the wet clutch, such as rotating speed, flow rate and inlet temperature of the lubricant, clutch sizes, and groove types, by using the correlations of the heat convection coefficient. The correlations were obtained from 96 experiments that were designed to study the effects of the design parameters. The coefficients of the correlations were determined by the non-dominated sorting genetic algorithm (NSGA-II) to minimize errors between the simulated and the experimental results. The simulated results were compared with the experimental results to demonstrate the validity of the model and the correlations by using the percentage error, the root-mean-square error, and the correlation coefficient. The validation parameters were in good agreement with the experimental results.

A Thermal Model to Predict Tool Temperature in Machining of Ti-6Al-4V Alloy With an Atomization-Based Cutting Fluid Spray System

2016 ◽  
Author(s):  
Asif Tanveer ◽  
Deepak Marla ◽  
Shiv G. Kapoor
Keyword(s):  
Heat Transfer ◽  
Interaction Model ◽  
Spray Cooling ◽  
Droplet Surface ◽  
Cutting Fluid ◽  
Design Parameters ◽  
Transfer Model ◽  
Tool Temperature ◽  
Spray System ◽  
Heat Transfer Phenomenon

In this study a heat transfer model of machining of Ti-6Al-4V under the application of atomization-based cutting fluid spray coolant is developed to predict the temperature of the cutting tool. Owing to high tool temperature involved in machining of Ti-6Al-4V, the model considers film boiling as the major heat transfer phenomenon. In addition, the design parameters of the spray for effective cooling during machining are derived based on droplet-surface interaction model. Machining experiments are conducted and the temperatures are recorded using the inserted thermocouple technique. The experimental data are compared with the model predictions. The temperature field obtained is comparable to the experimental results, confirming that the model predicts tool temperature during machining with ACF spray cooling satisfactorily.

Experimental Investigation of Single-Phase Cooling in Embedded Microchannels: 3D Manifold Heat Exchanger With R-245fa

2019 ◽  
Author(s):  
Ki Wook Jung ◽  
Hyoungsoon Lee ◽  
Chirag Kharangate ◽  
Feng Zhou ◽  
Mehdi Asheghi ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Single Phase ◽  
Heat Fluxes ◽  
Experimental Results ◽  
Maximum Temperature ◽  
Inlet Temperature ◽  
Fluid Temperature ◽  
Ir Camera

Abstract High performance and economically viable thermal cooling solutions must be developed to reduce weight and volume, allowing for a wide-spread utilization of hybrid electric vehicles. The traditional embedded microchannel cooling heat sinks suffer from high pressure drop due to small channel dimensions and long flow paths in 2D-plane. Utilizing direct “embedded cooling” strategy in combination with top access 3D-manifold strategy reduces the pressure drop by nearly an order of magnitude. In addition, it provides more temperature uniformity across large area chips and it is less prone to flow instability in two-phase boiling heat transfer. Here, we present the experimental results for single-phase thermofluidic performance of an embedded silicon microchannel cold-plate bonded to a 3D manifold for heat fluxes up to 300 W/cm2 using single-phase R-245fa. The heat exchanger consists of a 52 mm2 heated area with 25 parallel 75 × 150 μm2 microchannels, where the fluid is distributed by a 3D-manifold with 4 micro-conduits of 700 × 250 μm2. Heat is applied to the silicon heat sink using electrical Joule-heating in a metal serpentine bridge and the heated surface temperature is monitored in real-time by Infra-red (IR) camera and electrical resistance thermometry. The experimental results for maximum and average temperatures of the chip, pressure drop, thermal resistance, average heat transfer coefficient for flow rates of 0.1, 0.2. 0.3 and 0.37 lit/min and heat fluxes from 25 to 300 W/cm2 are reported. The proposed Embedded Microchannels-3D Manifold Cooler, or EMMC, device is capable of removing 300 W/cm2 at maximum temperature 80 °C with pressure drop of less than 30 kPa, where the flow rate, inlet temperature and pressures are 0.37 lit/min, 25 °C and 350 kPa, respectively. The experimental uncertainties of the test results are estimated, and the uncertainties are the highest for heat fluxes < 50 W/cm2 due to difficulty in precisely measuring the fluid temperature at the inlet and outlet of the micro-cooler.

Numerical Modeling of Multidirectional Flow and Heat Transfer in Graphitic Foams

2009 ◽  
Vol 131 (5) ◽  
Author(s):  
S. A. Mohsen Karimian ◽  
Anthony G. Straatman
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Pore Structure ◽  
Linear Models ◽  
A Priori ◽  
Experimental Results ◽  
Transfer Model ◽  
Thermal Dispersion ◽  
Wide Range ◽  
Graphitic Foam

To investigate the feasibility of the use of foams with an interconnected spherical pore structure in heat transfer applications, models for heat transfer and pressure drop for this type of porous materials are developed. Numerical simulations are carried out for laminar multidirectional thermofluid flow in an idealized pore geometry of foams with a wide range of geometry parameters. Semiheuristic models for pressure drop and heat transfer are developed from the results of simulations. A simplified solid-body drag equation with an extended high inertia term is used to develop the hydraulic model. A heat transfer model with a nonzero asymptotic term for very low Reynolds numbers is also developed. To provide hydraulic and heat transfer models suitable for a wide range of porosity, only a general form of the length-scale as a function of pore structure is defined a priori, where the parameters of the function were determined as part of the modeling process. The proposed ideal models are compared to the available experimental results, and the source of differences between experimental results and the ideal models is recognized and then calibrated for real graphitic foam. The thermal model is used together with volume-averaged energy equations to calculate the thermal dispersion in graphitic foam. The results of the calculations show that the linear models for thermal dispersion available in literature are oversimplified for predicting thermal dispersion in this type of porous material.

Design of Cryogenic Centrifugal Compressor Stages With Heat Transfer Considerations

2019 ◽  
Author(s):  
Jin Xiong ◽  
Yingkun Zhang ◽  
Penghua Guo ◽  
Jingyin Li
Keyword(s):  
Heat Transfer ◽  
Centrifugal Compressor ◽  
Design Method ◽  
Superconducting Magnet ◽  
High Energy ◽  
Design Parameters ◽  
Inlet Temperature ◽  
Outlet Section ◽  
Heat Leakage ◽  
Stage Performance

Abstract The large superconducting magnet are widely used and play an important role in nuclear fusion device, high-energy accelerator, space target infrared and other forefront fields. In this paper, we design several cryogenic centrifugal compressor stages for helium refrigerator with 3.3K∼11K inlet temperature, used in exhausting the low-pressure and low-temperature saturated helium steam, further producing superfluid helium and cooling the large superconducting magnet. Due to the cryogenic compressor running environment and the internal structure, about 30W heat leakage from impeller hubs and the end of shafts into the flow passages are unavoidable, and it is necessary to consider this heat leakage in the centrifugal compressor impeller design. Firstly, adding the heat leakage into thermodynamic process and centrifugal compressor effective formula, then adjusting the inlet and outlet design parameters according to the heat transfer rate and make the preliminarily designs of each stage of the compressor. Four different methods for varying p design condition parameters are compared by CFD simulation. The 3-D impellers are designed by the Streamline Curvature Method, and the vaneless diffusers and volutes are designed by the inlet and outlet section aerodynamic parameters. When the best design method is determined, the blade profiles are further adjusted in order to improve the stage performance. Finally, the characteristic curves under variable working conditions and the generalized stage performance curves of each stage are calculated. In this paper, we delve into a high efficiency centrifugal compressor stage design method with the consideration of heat transfer effect. In the next step, more running data will be obtained after the further experiments and the long-term operation.

Unsteady Heat Transfer in a Motored I.C. Engine Cylinder

1970 ◽  
Vol 185 (1) ◽  
pp. 1139-1148 ◽  
Author(s):  
H. Hassan
Keyword(s):  
Heat Transfer ◽  
Empirical Data ◽  
Experimental Results ◽  
Gas Velocity ◽  
Flat Plates ◽  
Unsteady Heat Transfer ◽  
New Approach ◽  
Transfer Data ◽  
Engine Cylinder ◽  
Engine Cycle

After a brief review of the existing formulae for the unsteady heat transfer in I.C. engine cylinders, a new approach is described. It is shown that the existing empirical heat transfer data of forced convective case for the flat plates or pipes can be used to predict the heat transfer. Experimental results obtained on a motored engine are presented which include the measurement of gas velocity, temperature, pressure and metal surface temperature to obtain the convective unsteady heat transfer through the engine cycle. The experimental results are compared with the empirical data on a flat plate and it is concluded that the agreement is within 20 per cent.

Soret, Dufour and Heat by Chemical Reaction Effects in a Chemical Vapor Deposition Optical Fiber Coating Process

2005 ◽  
Author(s):  
Wei Huang ◽  
Wilson K. S. Chiu
Keyword(s):  
Heat Transfer ◽  
Chemical Vapor Deposition ◽  
Optical Fiber ◽  
Chemical Reactions ◽  
Vapor Deposition ◽  
Soret Effect ◽  
Chemical Vapor ◽  
Operating Conditions ◽  
Inlet Temperature ◽  
Transfer Model

In this paper, we studied the effect of thermal diffusion (Soret effect), the heat flux due to species concentration gradient (Dufour effect) and the heat by chemical reactions in a chemical vapor deposition (CVD) process used to hermetically coat optical fibers. Using a previously developed mass and heat transfer model to investigate the transport phenomena in this process, the Soret and Dufour effects are compared to ordinary mass diffusion. The thermal conductivity, molecular diffusivity and thermal diffusivity are calculated using a multi-component model. The contribution of heat of chemical reactions to overall heat transfer in the CVD is also discussed. Soret effect and heat by chemical reactions are found to be very important in this process, and their effect is related to operating conditions such as draw speed and optical fiber inlet temperature.

scholarly journals Heat Transfer Characteristics of Thermoelectric Generator System for Waste Heat Recovery from a Billet Casting Process: Experimental and Numerical Analysis

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 601
Author(s):  
Saurabh Yadav ◽  
Jie Liu ◽  
Man Sik Kong ◽  
Young Gyoon Yoon ◽  
Sung Chul Kim
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Thermoelectric Generator ◽  
Cold Water ◽  
Waste Heat ◽  
Experimental Results ◽  
Inlet Temperature ◽  
Heat Transfer Characteristics ◽  
One Dimensional ◽  
Transfer Characteristics

In this study, experiments were performed to use the waste heat in a billet casting industry utilizing bismuth telluride thermoelectric generators (TEGs). Four d-type absorber plates made of copper were installed above the manufactured billet during the cooling process. Three sides of each absorber plate were attached to thermoelectric units. Therefore, a total of 12 units of the thermoelectric system were found to generate a power of 339 W. The power density of the TEG system was found to be 981 W/m2 while running the system at the operating voltage of the battery energy storage system (58 V). A one-dimensional numerical simulation was carried out using FloMASTERTM v9.1 (Mentor Graphics Corporation, Siemens, Dallas, TX, USA) to verify the experimental results, and the numerical results were found to exhibit good agreement with the experimental results. Furthermore, a one-dimensional numerical simulation was carried out to obtain the heat transfer characteristics at varying flow rates of cold water (Reynolds number = 2540–16,943) and at different inlet temperatures (10–25 °C) for the cold side of the TEG. The results indicate that the performance of the thermoelectric generator increases with an increase in the cold-water flow rate and a decrease in the inlet temperature of the cold water.

Heat and Mass Transfer in a CVD Optical Fiber Coating Process

Volume 3 ◽  
2004 ◽  
Author(s):  
Wei Huang ◽  
Wilson K. S. Chiu
Keyword(s):  
Heat Transfer ◽  
Optical Fiber ◽  
Reaction Kinetics ◽  
Gas Flow ◽  
Chemical Vapor ◽  
Parameter Study ◽  
Inlet Temperature ◽  
Transfer Model ◽  
Phase Reaction ◽  
Empirical Parameter

In this paper, we study the chemical vapor deposition (CVD) process used to hermetically coat optical fibers during draw. Temperature is calculated by coupling radiation and convection heat transfer by the reactor walls and gas flow with a radially-lumped heat transfer model for the moving optical fiber. Multi-component species diffusion is modeled using the Maxwell-Stefan equations. Gas-phase reaction kinetics is modeled using a 2-step chemical kinetics mechanism derived from RRKM theory with detailed kinetics data compiled from literature. Surface reaction kinetics are described using collision theory in which a sticking coefficient is used as an empirical parameter to predict surface reactions. A parameter study is carried out with various optical fiber inlet temperature and drawing speed, and validated with experiment results.

A Methodology for Measuring Turbocharger Adiabatic Maps in a Gas-Stand and its Usage for Calibrating Control Oriented and 1D Models at Early ICE Design Stages

2019 ◽  
Author(s):  
José Ramón Serrano ◽  
Francisco José Arnau ◽  
Luis Miguel García-Cuevas ◽  
Alejandro Gómez-Vilanova ◽  
Stephane Guilain ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Internal Combustion Engines ◽  
Gas Flow ◽  
System Analysis ◽  
Pressure Ratio ◽  
Inlet Temperature ◽  
Boost Pressure ◽  
Gas Temperature ◽  
Hot Gas ◽  
The Impact

Abstract Turbocharged engines are the standard architecture for designing efficient spark ignition and compression ignition reciprocating internal combustion engines (ICE). Turbochargers characterization and modeling are basic tasks for the analysis and prediction of the whole engine system performance and this information is needed in quite early stages of the engine design. Turbocharger characteristics (efficiency, pressure ratio, mass flow rates...) traditionally rely in maps of pseudo non-dimensional variables called reduced variables. These maps must be used by reciprocating ICE designer and modeler not only for benchmarking of the turbocharger, but for a multiplicity of purposes, i.e: assessing engine back-pressure, boost pressure, load transient response, after-treatment inlet temperature, intercooler inlet temperature, low pressure EGR temperature, ... Maps of reduced variables are measured in gas-stands with steady flow but non-standardized fluids conditioning; neither temperatures nor flows. In concrete: turbine inlet gas temperature; lubrication-oil flow and temperature; water-cooling flow and turbo-machinery external heat transfer are non-standardized variables which have a big impact in assessing said multiplicity of purposes. Moreover, adiabatic efficiency, heat losses and friction losses are important data, hidden in the maps of reduced variables, which depend on the testing conditions as much as on the auxiliary fluids temperature and flow rate. In this work it is proposed a methodology to standardize turbochargers testing based in measuring the maps twice: in close to adiabatic and in diathermal conditions. Along the paper it is discussed with special detail the impact of the procedure followed to achieve said quasi-adiabatic conditions in both the energy balance of the turbocharger and the testing complexity. As a conclusion, the paper proposes a methodology which combines quasi-adiabatic tests (cold and hot gas flow) with diathermal tests (hot gas flow) in order to extract from a turbocharger gas-stand all information needed by engine designers interested in controlling or 1D-modelling the ICE. The methodology is completed with a guide for calibrating said control-oriented turbocharger models in order to separate aerodynamic efficiency (adiabatic) from heat transfer losses and from friction losses in the analysis of the turbocharger performance. The outsourced calibration of the turbocharger model allows avoiding uncertainties in the global ICE model calibration, what is very interesting for turbochargers benchmarking at early ICE-turbo matching stages or for global system analysis at early control design stages.

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