Nanoparticle Redistribution During Magnetic Nanoparticle Hyperthermia: Multi-Physics Porous Medium Model Analyses

2012 ◽  
Author(s):  
Anilchandra Attaluri ◽  
Robert Ivkov ◽  
Ronghui Ma ◽  
Liang Zhu
Keyword(s):  
Heat Transfer ◽  
Porous Media ◽  
Magnetic Nanoparticle ◽  
Thermal Damage ◽  
Heat Transfer Model ◽  
Transfer Model ◽  
Model Based ◽  
Porous Media Model ◽  
Magnetic Nanoparticle Hyperthermia ◽  
And Diffusion

A coupled theoretical framework comprising a suspension of nanoparticles transport in porous media model and a heat transfer model is developed to address nanoparticle redistribution during heating. Nanoparticle redistribution in biological tissues during magnetic nanoparticle hyperthermia is described by a multi-physics model that consists of five major components: (a) a fully saturated porous media model for fluid flow through tissue; (b) nanoparticle convection and diffusion; (c) heat transfer model based on heat generation by local nanoparticle concentration; (d) a model to predict tissue thermal damage and corresponding change to the porous structure; and (e) a nanoparticle redistribution model based on the dynamic porosity and diffusion diffusivity. The integrated model has been used to predict the structural damage in porous tumors and its effect on nanoparticle-induced heating in tumors. Thermal damage in the vicinity of the tumor center that is predicted by the Arrhenius equation increases from 14% with 10 minutes of heating to almost 99% after 20 minutes. It then induces an increased tumor porosity that increases nanoparticle diffusivity by seven-fold. The model predicts thermal damage induced by nanoparticle redistribution increases by 20% in the radius of the spherical tissue region containing nanoparticles. The developed model has demonstrated the feasibility of enhancing nanoparticle dispersion from injection sites using targeted thermal damage.

Identification for Control of Low Pressure Die Casting

2010 ◽  
Author(s):  
XinMei Shi ◽  
Daan M. Maijer ◽  
Guy Dumont
Keyword(s):  
Heat Transfer ◽  
State Space ◽  
Die Casting ◽  
State Space Model ◽  
Heat Transfer Model ◽  
Transfer Model ◽  
Process Data ◽  
Space Model ◽  
Model Based ◽  
Virtual Process

Controlling and eliminating defects, such as macro-porosity, in die casting processes is an on-going challenge for manufacturers. Current strategies for eliminating defects focus on the execution of a pre-set casting cycle, die structure design or the combination of both. To respond to process variability and mitigate its negative effects, advanced process control methodologies may be employed to dynamically adjust the operational parameters of the process. In this work, a finite element heat transfer model, validated by comparison with experimental data, has been developed to predict the evolution of temperatures and the volume of liquid encapsulation in an experimental casting process. A virtual process, made up of the heat transfer model and a wrapper script for communication, has been employed to simulate the continuous operation of the real process. A stochastic state-space model, based on data from measurements and the virtual process, has been developed to provide a reliable representation of this virtual process. The parameters of the deterministic portion result from system identification of the virtual process, whereas the parameters of the stochastic portion arise from the analysis and comparison of measurement data with virtual process data. The resulting state-space model, which can be extended to a multi-input multi-output model, will facilitate the design of a model-based controller for this process.

CFD Analysis of the EGR Cooler’s Heat Transfer Performance

2014 ◽  
Vol 889-890 ◽  
pp. 309-315
Author(s):  
Zhi‘en Liu ◽  
Yu Xu
Keyword(s):  
Heat Transfer ◽  
Boundary Conditions ◽  
Cfd Simulation ◽  
Exchange Process ◽  
Decomposition Methods ◽  
Heat Transfer Model ◽  
Transfer Model ◽  
Middle Portion ◽  
Model Based ◽  
Egr Cooler

A CFD simulation of the performance of an EGR cooler was carried out. Considering the differences between the heat exchange process of its inlet portion, middle portion and outlet portion, this simulation divided the model into three parts and analyzed them in turn. For the inlet and outlet portion, the convective heat transfer model was applied; while for the middle portion, an air-solid-liquid three-phase heat transfer model, based on strong coupling was extracted. According to the geometry continuity of the model, the boundary conditions of the middle portion was determined by the simulation result of the inlet portion, and the boundary conditions of the outlet portion was determined by the simulation result of the middle portion. Ultimately, we can gain the overall temperature distribution of the EGR cooler under the premise of ensuring the accuracy of the heat transfer model and minimizing the computation. This model based on decomposition methods was applied to the temperature field simulation under different EGR cooler rate and the simulation results were in good agreement with the experimental results.

SIMPLIFIED HEAT TRANSFER MODEL FOR STABELIZED PREMIXED FLA-MES IN POROUS MEDIA

2017 ◽  
Vol 11 (3) ◽  
Author(s):  
Aldélio Caldeira Bueno ◽  
Isabela Martins Maranhão ◽  
Thiaron Pereira da Silva ◽  
Rafaela Pedroso Catureba
Keyword(s):  
Heat Transfer ◽  
Porous Media ◽  
Heat Transfer Model ◽  
Transfer Model

Leakage, heat transfer and thermal deformation analysis method for contacting finger seals based on coupled porous media and real structure models

2020 ◽  
Vol 234 (10) ◽  
pp. 2077-2093
Author(s):  
Qiang Wang ◽  
Ya-Ping Hu ◽  
Hong-Hu Ji
Keyword(s):  
Heat Transfer ◽  
Porous Media ◽  
Thermal Deformation ◽  
Flow Direction ◽  
Frictional Heating ◽  
Real Structure ◽  
Deformation Analysis ◽  
Transfer Model ◽  
Analysis Method ◽  
Porous Media Model

Finger seal is a type of compliant seal configuration that has superior sealing performance compared with conventional labyrinth seals and brush seals. However, complex working conditions lead to leakage, thermal gradient and deformation, which can be more serious for a contacting finger seal due to frictional heating. In this paper, a leakage and thermal performance analysis method coupled with porous media and a real structure model was developed to numerically simulate the leakage, heat transfer and thermal deformation characteristics of a contacting finger seal. The method innovatively established a porous media fluid dynamics and heat transfer model and modified the frictional heating model by introducing the concept of a friction work conversion ratio. Then, the thermal deformation of the fingers was calculated on the basis of pressure and temperature results by using the thermal-stress module of ANSYS Workbench. The results show that the leakage analysis porous media model has good calculation accuracy and most of the fluid leaks through the finger foot, while the pressure drops mainly in this field. The highest finger temperature occurs at the downstream side of the contact surface between the finger foot and the rotor. The largest thermal deformation of each laminate occurs at the finger foot toe and increases slightly along the flow direction. Additionally, the largest relative circumferential thermal deformation can reduce the gap between the fingers by approximately 5%, which is beneficial for reducing leakage. It is suggested to increase the seal inner diameter at the finger foot toe but decrease it at the finger foot heel during the design process to decrease wear and leakage.

Sign in / Sign up

Export Citation Format

Share Document