scholarly journals MODELLING OF TEMPERATURE FIELD DISTRIBUTION IN BIOLOGICAL TISSUE THERMAL LESION

2021 ◽  
Vol 297 (3) ◽  
pp. 208-215
Author(s):  
JULIA SHTEFURA ◽  
◽  
KOSTIANTYN SHEVCHENKO ◽  
OLEH KOZYR ◽  
OLEKSII STATSENKO ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Temperature Field ◽  
Heat Exchange ◽  
Field Distribution ◽  
Thermal Regime ◽  
Biological Tissue ◽  
Thermal Model ◽  
Temperature Field Distribution ◽  
Thermal Lesion ◽  
Exchange Processes

Early determination of the thermal lesion degree in case of scald accelerates the treatment process and increases its effectiveness. The thermal lesion degree can be evaluated by determining the temperature difference between healthy and injured areas of biological tissue. For this purpose, a model of biological tissue in the form of a multilayer structure can be used. Heat exchange processes in such a structure are described by a generalized thermal model. Such structure contains conditionally flat heat sources located in each layer, which have the form of a developed network of blood vessels. The considered model of biological tissue quite accurately describes the heat exchange processes in body tissues. The article considers heat exchange processes that take place in biological tissue and a number of assumptions that should be used to mathematically describe these processes were identified. During the analysis of heat transfer process, the equations of temperature distribution in the tissue layers and the boundary conditions that describe the thermal interaction of the model with the environment are determined. As a result, the model of the stationary thermal regime of a biological tissue fragment in the form of a generalized thermal model and a mathematical model of the temperature field distribution in this fragment is obtained. This model is determined by many parameters, which are divided into 3 groups: thermophysical parameters; structural and topological parameters; parameters of the blood vascular system. Models of the particular fragment thermal regime are unequivocally determined by a combination of these parameters. For the analysis of temperature in any point of biological tissue modelled part mathematical model of temperature field distribution in stationary mode was developed. This model allows reasonable approach to the thermal lesion degree evaluation on the basis of the surface temperature difference between healthy and injured areas of tissue.

scholarly journals Research on the influence of air-gap eccentricity on the temperature field of a motorized spindle

2021 ◽  
Vol 12 (1) ◽  
pp. 109-122
Author(s):  
Xiaohu Li ◽  
Jinyu Liu ◽  
Cui Li ◽  
Jun Hong ◽  
Dongfeng Wang
Keyword(s):  
Temperature Field ◽  
Field Distribution ◽  
Thermal Model ◽  
Magnetic Loss ◽  
Air Gap ◽  
Machining Accuracy ◽  
Motorized Spindle ◽  
Temperature Field Distribution ◽  
Angular Contact Ball Bearing ◽  
Important Indicator

Abstract. The air-gap state between the stator and rotor is an important indicator to measure the performance of a motorized spindle. It affects the temperature field distribution of the motorized spindle and the machining accuracy of the mechanical parts. Since the accurate thermal model is the basis of the research on the temperature field distribution of the motorized spindle, in this paper, firstly, the mechanical loss, electrical loss and magnetic loss of the motor under different air-gap eccentricities are calculated and the heat-generating power of an angular-contact ball bearing is obtained based on Harries contact theory. Secondly, the thermal model of the motorized spindle is established and the steady-state temperature field of the motorized spindle is simulated by using ANSYS, and the influence of air-gap eccentricity on the temperature field of the motorized spindle is discussed. Finally, the circumferential temperature field distribution of the motorized spindle with the air-gap eccentricity is verified by experiment. The results show that the air-gap eccentricity has a significant influence on the non-uniform temperature field of the motorized spindle.

scholarly journals Three-Dimensional Electro-Thermal Analysis of a New Type Current Transformer Design for Power Distribution Networks

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1792
Author(s):  
Bingbing Dong ◽  
Yu Gu ◽  
Changsheng Gao ◽  
Zhu Zhang ◽  
Tao Wen ◽  
...  
Keyword(s):  
Boundary Condition ◽  
Temperature Field ◽  
Temperature Gradient ◽  
Field Distribution ◽  
Distribution Network ◽  
Current Transformer ◽  
Internal Temperature ◽  
Temperature Field Distribution ◽  
Type Design ◽  
New Type

In recent years, the new type design of current transformer with bushing structure has been widely used in the distribution network system due to its advantages of miniaturization, high mechanical strength, maintenance-free, safety and environmental protection. The internal temperature field distribution is an important characteristic parameter to characterize the thermal insulation and aging performance of the transformer, and the internal temperature field distribution is mainly derived from the joule heat generated by the primary side guide rod after flowing through the current. Since the electric environment is a transient field and the thermal environment changes slowly with time as a steady field under the actual conditions, it is more complex and necessary to study the electrothermal coupling field of current transformer (CT). In this paper, a 3D simulation model of a new type design of current transformer for distribution network based on electric-thermal coupling is established by using finite element method (FEM) software. Considering that the actual thermal conduction process of CT is mainly by conduction, convection and radiation, three different kinds of boundary conditions such as solid heat transfer boundary condition, heat convection boundary condition and surface radiation boundary condition are applied to the CT. Through the model created above, the temperature rise process and the distribution characteristics of temperature gradient of the inner conductor under different current, different ambient temperatures and different core diameters conditions are studied. Meanwhile, the hottest temperature and the maximum temperature gradient difference are calculated. According to this, the position of weak insulation of the transformer is determined. The research results can provide a reference for the factory production of new type design of current transformer.

scholarly journals The study of three-dimensional temperature field distribution reconstruction using ultrasonic thermometry

AIP Advances ◽  
2016 ◽  
Vol 6 (7) ◽  
pp. 075007 ◽  
Author(s):  
Ruixi Jia ◽  
Qingyu Xiong ◽  
Kai Wang ◽  
Lijie Wang ◽  
Guangyu Xu ◽  
...  
Keyword(s):  
Temperature Field ◽  
Field Distribution ◽  
Three Dimensional ◽  
Temperature Field Distribution

Simulation and Optimization of Temperature Field of Tank Cover with Super Large Diameter during the Creep Aging Forming Process

2021 ◽  
Vol 315 ◽  
pp. 3-9
Author(s):  
Yuan Gao ◽  
Li Hua Zhan ◽  
Hai Long Liao ◽  
Xue Ying Chen ◽  
Ming Hui Huang
Keyword(s):  
Temperature Field ◽  
Field Distribution ◽  
Temperature Difference ◽  
Single Stage ◽  
Maximum Temperature ◽  
Heating Process ◽  
Temperature Field Distribution ◽  
Two Stage ◽  
Maximum Temperature Difference ◽  
Forming Accuracy

The uniformity of temperature field distribution in creep aging process is very important to the forming accuracy of components. In this paper, the temperature field distribution of 2219 aluminum alloy tank cover during aging forming is simulated by using the finite element software FLUENT, and a two-stage heating process is proposed to reduce the temperature field distribution heterogeneity. The results show that the temperature difference of the tank cover is large in the single-stage heating process, and the maximum temperature difference is above 27°C,which seriously affects the forming accuracy of the tank cover. With two-stage heating process, the temperature difference in the first stage has almost no direct impact on the forming accuracy of the top cover. In the second stage, the temperature difference of the tank cover is controlled within 10°C, compared with the single-stage heating, the maximum temperature difference is reduced by more than 17°C. The two-stage heating effectively reduces the heterogeneity of the temperature field of the top cover. The research provides technical support for the precise thermal mechanical coupling of large-scale creep aging forming components.

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