scholarly journals CFD Model for Aircraft Ground Deicing: Verification and Validation of an Extended Enthalpy-Porosity Technique in Particulate Two Phase Flows

Fluids ◽  
2021 ◽  
Vol 6 (6) ◽  
pp. 210
Author(s):  
Sami Ernez ◽  
François Morency
Keyword(s):  
Heat Transfer ◽  
Melting Process ◽  
Transient Temperature ◽  
Ice Melting ◽  
Two Phase ◽  
Transient Temperature Field ◽  
Proposed Model ◽  
Deicing Fluid ◽  
Cfd Method ◽  
Surface Ice

Researchers have focused in the last five years on modelling the aircraft ground deicing process using CFD (computational fluid dynamics) in order to reduce its costs and pollution. As preliminary efforts, those studies did not model the ice melting nor the diffusion between deicing fluids and water resulting from the melting process. This paper proposes a CFD method to simulate this process filling these gaps. A particulate two-phase flow approach is used to model the spray impact on ice near the contaminated surface. Ice melting is modelled using an extended version of the enthalpy-porosity technique. The water resulting from the melting process is diffused into the deicing fluid forming a single-phase film. This paper presents a new model of the process. The model is verified and validated through three steps. (i) verification of the species transport. (ii) validation of the transient temperature field of a mixture. (iii) validation of the convective heat transfer of an impinging spray. The permeability coefficient of the enthalpy-porosity technique is then calibrated. The proposed model proved to be a suitable candidate for a parametric study of the aircraft ground deicing process. On the validation test cases, the precision of heat transfer prediction exceeds 88%. The model has the ability of predicting the deicing time and the deicing fluid quantities needed to decontaminate a surface.

Numerical Simulation Model of Electrothermal De-Icing Process on Composite Substrate

2020 ◽  
Author(s):  
Xiaofeng Guo ◽  
Zhiqiang Guo ◽  
Qian Yang ◽  
Wei Dong
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Thermal Properties ◽  
Temperature Distribution ◽  
Simulation Model ◽  
Melting Process ◽  
Ice Melting ◽  
Melted Zone ◽  
Composite Substrate ◽  
Cfrp Composite

Abstract A numerical simulation model of electrothermal de-icing process on carbon fiber reinforced polymer (CFRP) composite is conducted to study the effect of thermal properties of the substrate on the ice melting process. A novel melting model which is based on the enthalpy-porosity method is applied to study the transient ice melting process and heat transfer of the de-icing sys-tem. Multi-layered electrothermal de-icing systems including composites with different fiber orientation are used to analyze the effects of orthotropic heat conductivity of the CFRP composite on the ice melting process and heat transfer. Movement of the ice-water interface, the melted zone thickness and the melted zone area on CFRP composite are investigated on the three-dimensional electrothermal de-icing unit. The effects of thermal properties of substrate on the temperature distribution of the ice-airfoil interface are analyzed. The computational results show that the thermal properties of substrates affect the temperature on the ice-airfoil interface, the temperature distribution in the substrate, ice melting area, ice melting rate and ice melting volume significantly. The time that ice starts to melt on the CFRP composite substrate is earlier than that on the metal substrate. However, it takes more time for the ice to melt completely on the ice-CFRP interface than that on the ice-metal inter-face. The orthotropic heat conductivity of CFRP composite results in strong directivity of the melting area on the ice-CFRP in-terface. A ratio parameter is defined to represent the matching degree of substrate materials and geometry model of de-icing system. The simulation model can be applied to study electrothermal de-icing system of nacelle inlet and airfoil made of composite. The results in present work is also helpful to predict the change of temperature during de-icing process and provide guidelines for the optimizing the electrothermal de-icing system to reduce power consumption according to the fiber structure of composite.

Mechanisms of Gas Turbine Regenerator Fouling

1967 ◽  
Author(s):  
James A. Miller
Keyword(s):  
Heat Transfer ◽  
Particulate Matter ◽  
Theoretical Model ◽  
Gas Turbine ◽  
Two Phase ◽  
Degradation Data ◽  
Proposed Model ◽  
Controlling Mechanism ◽  
Adhesive Coating ◽  
Phase Process

Possible mechanisms of gas turbine regenerator fouling are examined and compared with extant experimental evidence. A theoretical model of fouling which encompasses a two-phase process is proposed. It is shown that the controlling mechanism is the condensation of heavy hydrocarbon isomers which form an adhesive coating in which particulate matter subsequently become entrapped. Typical overall heat transfer and pressure drop degradation data are presented which tend to support the proposed model.

scholarly journals Transient Temperature Field Model of Wear Land on the Flank of End Mills: A Focus on Time-Varying Heat Intensity and Time-Varying Heat Distribution Ratio

2019 ◽  
Vol 9 (8) ◽  
pp. 1698 ◽  
Author(s):  
Du ◽  
Yue ◽  
Liu ◽  
Liang ◽  
Wang ◽  
...  
Keyword(s):  
Temperature Field ◽  
High Speed ◽  
Field Model ◽  
Transient Temperature ◽  
Time Varying ◽  
Peripheral Milling ◽  
Transient Temperature Field ◽  
Proposed Model ◽  
Temperature Field Model ◽  
End Mills

Modelling methods for the transient temperature field of wear land on the flank of end mills have been proposed to address the challenges of inaccurate prediction in the temperature field of end mills during the high-speed peripheral milling of Ti6Al4V that is a titanium alloy. A transient temperature rise model of wear land on the flank of end mills was constructed under the influence of heat sources in the primary shearing zone (PSZ), rake-chip zone (RCZ), flank-workpiece zone (FWZ), and dissipating heat source. Then the transient temperature field model of wear land on the flank of end mills was constructed. Finally, the transient temperature field model of wear land on the flank of end mills was constructed. Comparison of simulation result and experimental data verified the accuracy of the model. In sum, the proposed model may provide a temperature model support for future studies of flank wear rate in end mill modeling.

Prediction and Control of Weld Width of Deep Drawing Steel Laser Tailored Blanks

2013 ◽  
Vol 652-654 ◽  
pp. 2270-2273
Author(s):  
Xin Cheng Li ◽  
Jian Hua He ◽  
Wei Xing Zhu ◽  
Wan Li Du
Keyword(s):  
Transient Temperature ◽  
Plate Temperature ◽  
Test Plate ◽  
Weld Width ◽  
Finite Element Software ◽  
Transient Temperature Field ◽  
Tailored Blanks ◽  
Proposed Model ◽  
Prediction And Control ◽  
And Control

The weld width of laser welding not only affects the tailor welded blank forming properties, but also leads to fracture failure to a great extent during the stamping process. In order to optimize the weld process and ensure laser welded tailored blanks (LWTBs) forming properties, the weld width should be predicted and controlled. Firstly, the transient temperature field distributions are simulated by means of the finite element software. Then the weld widths are calculated based on the analysis of test plate temperature distribution. Additionally, weld width prediction model is put forward by means of Partial least squares (PLS). And the forecasting relative error of weld width is below 5%. Then it can be concluded that the proposed model is reasonable and applicable.

Heat and Mass Transfer Characteristics of a Temperature and Concentration Combined Convection Due to a Vertical Ice Plate Melting

2003 ◽  
Vol 125 (1) ◽  
pp. 39-47 ◽  
Author(s):  
M. Sugawara ◽  
Thomas F. Irvine ◽  
M. Tago
Keyword(s):  
Aspect Ratio ◽  
Initial Temperature ◽  
Melting Process ◽  
Melting Rate ◽  
Transient Temperature ◽  
Liquid Region ◽  
Ice Melting ◽  
Melting Front ◽  
Diffusive Convection ◽  
Double Diffusive

The melting of a vertical ice plate into a calcium chloride aqueous solution (CaCl2-H2O mixture) in a rectangular cavity is considered numerically and experimentally. The ice plate melts spontaneously with decreasing temperature at the melting front even when there exists no initial temperature difference between ice and liquid. Visual observations in the liquid reveal a complicated natural convection affected by the concentration/temperature gradients which appear near the melting front. Melt water gradually contaminates an upper region in the initially homogeneous liquid, that causes the melting rate to decrease. Aspect ratio H/W of the liquid region does not affect the melting rate within an early melting stage, however large aspect ratio causes the melting rate to decrease during the melting process. A two-dimensional numerical model reflecting actual ice melting conditions predicts, approximately, the transient melting mass, and the transient temperature/concentration decrease in the melting system. It is seen that the Sherwood number at the melting front is larger when compared with previous results concerning double diffusive convection. The Nusselt number at the melting front is quantitatively considered experimentally and analytically.

Research on Gradient Heat Treatment of Dual-Property Disk for Alloy FGH96

2013 ◽  
Vol 747-748 ◽  
pp. 783-787
Author(s):  
Yu Wang ◽  
Jin Wen Zou ◽  
Guo Qing Zhang ◽  
Wu Xiang Wang
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Heat Treatment ◽  
Transient Temperature ◽  
Heating Process ◽  
Fixture Design ◽  
Dual Property ◽  
Transient Temperature Field ◽  
Heat Treated ◽  
Treatment Experiment

The transient temperature field in the dual-property disk of alloy FGH96 was investigated during the solution heating process of the gradient heat treatment by numerical simulation. The temperature curves for the different locations of the disk were attained. Then, the gradient heat treatment experiment was carried out, and the heat profiles were obtained. The numerical and the experimental results were almost consistent. The method of heat transfer for the bore of the disk was changed evidently through effective fixture design during the gradient heat treatment. The gradient of temperature (ΔT) can reach 121 or more, which lead to a supersolvus heat treated rim and subsolvus heat treated bore for the disk.

Transient Heat Transfer in a Conducting Particle With Internal Radiant Absorption

1992 ◽  
Vol 114 (2) ◽  
pp. 304-309 ◽  
Author(s):  
A. Tuntomo ◽  
C. L. Tien
Keyword(s):  
Heat Transfer ◽  
Liquid Droplet ◽  
Local Maximum ◽  
Transient Heat Transfer ◽  
Maximum Temperature ◽  
Transient Temperature ◽  
Radiation Parameter ◽  
Current Effort ◽  
Transient Temperature Field ◽  
Conducting Particle

The objective of the present work is to analyze rigorously the transient heat transfer of an irradiated particle by treating the radiant absorption on a local basis. A new conduction-to-radiation parameter is introduced to characterize the relative importance of heat transfer by conduction as compared with that by radiation. The study on the transient temperature field as a function of conduction-to-radiation parameter establishes a criterion identifying the circumstances where heat transfer by radiation is so predominant that conduction is negligible. The current effort is also directed at developing a convenient method for predicting the transient local maximum temperature and explosion time delay of an intensely irradiated liquid droplet.

scholarly journals Modelling of Transient CO2/Water Flow in Wellbore considering Multiple Mass and Heat Transfer

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Xinxin Zhao ◽  
Xiangzhen Yan ◽  
Xiaohui Sun ◽  
Qing Zhao ◽  
Hongwei Jiang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Two Phase Flow ◽  
Coupled Model ◽  
Mass Conservation ◽  
Phase Flow ◽  
Co2 Solubility ◽  
Two Phase ◽  
Gas Kick ◽  
Proposed Model ◽  
Mass And Heat Transfer

A transient fully coupled model is proposed to investigate the two-phase flow of CO2 and water-based fluid in a wellbore, considering the complex mass and heat transfer in different flow patterns and dynamic coupling between the wellbore and reservoir. Based on mass conservation, momentum, and energy balance, the model employs a state-of-the-art equation of state and transport models to analyze the variations of multiphase flow behaviors and CO2 properties in a wellbore. Applied in the scenario of a drilled gas kick, the proposed model is used to simulate the processes of gas migration and two-phase flow in the wellbore. The results indicate that the CO2 solubility increases gradually with the increment of depth, the trend of which shows an abrupt change in 500-1000 m due to the phase transition of CO2. During kick development, the fronts of free gas and dissolved gas increase almost linearly with time. Through a comparison of CO2 and CH4 kicks, gas dissolution is found to significantly suppress the development process of CO2 kick. The error in kick prediction can reach 42% if the effect of gas dissolution is neglected. However, it can be neglected for CH4 kick.

Adaptive Thermal Modeling: A Concept for Measurement of Local Blood Perfusion in Heated Tissues

1986 ◽  
Vol 108 (4) ◽  
pp. 306-311 ◽  
Author(s):  
H. Arkin ◽  
M. M. Chen ◽  
K. R. Holmes
Keyword(s):  
Numerical Technique ◽  
Thermal Modeling ◽  
Blood Perfusion ◽  
Transient Temperature ◽  
Second Phase ◽  
Two Phase ◽  
Local Tissue ◽  
Transient Temperature Field ◽  
Near Future

A new Adaptive Thermal Modeling (ATM) method for the measurement of local tissue blood perfusion rate is introduced. The method is based on a two-phase numerical technique. The first phase includes a fast, finite difference scheme for solution of the transient temperature field. The second phase involves iterative corrections of the perfusion until the modeled temperatures coincide with those measured by the temperature sensors. The results obtained from computer generated “data”, as well as from laboratory experiments demonstrate the potential capability of the ATM method to continuously measure local perfusion rates in heated tissues. Rigorous analysis of the technique is planned for the near future so that it can be applied to in vivo measurements of local tissue blood perfusions.

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