Experimental and Numerical Study of Volt-Ampere Characteristics of a Packed Tube Heated by Joule Heating

This work is devoted to experimental and numerical studies of volt-ampere characteristics of a fixed bed heated by the Joule heating. The main feature of this type of fixed bed is internal heat generation using the Joule heat. The application is to provide the heat to chemically reacting gases flowing through the bed reactor. To validate our model a cylindrical packed bed is considered with a height of 11 cm and an internal diameter of 4.8 cm. This bed is filled with 86 balls made of carbon steel with a diameter of 1/2 inches (1.27 cm). For numerical simulation, open-source DEM software is used to generate the cylindrical packed bed. Electric field distribution is calculated using a new particle-unresolved DEM-based model coupled with a discrete heat transfer model to account for the temperature dependency of the electrical conductivity of steel particles. The results of the simulation were found to be in good agreement with experimental data.

OPTIMIZATION OF STATIONARY AND TRANSITIONAL OPERATING MODES OF THE ELECTRICAL COMPLEX IN METAL PROCESSING LINE

In the electrical complex “induction heater - deforming equipment”, the limiting performance of the complex is the induction heating unit. In this regard, an important task of increasing the effi ciency of the processing complex is to optimize both the design and operating parameters of the induction heating unit. It is shown that the main design parameter infl uencing the energy characteristics of the complex is the length of the heating system. When optimizing the total length of the heater, an iterative model of the process of induction heating of ferromagnetic billets is used. The power distribution algorithm along the length of a two-section heater is a piecewise continuous function. Optimization of the heater length according to the proposed method made it possible to reduce the heater length from 2.8 m to 2.1 m, i.e. by 25%. To search for eff ective control algorithms for non-stationary modes, a refi ned electrothermal model is proposed in the work. It takes into account the nonlinear dependence of the distribution of the power of the sources of internal heat release on the temperature distribution in the metal of the workpieces along the radial and axial coordinates. The problem of fi nding the optimal control of transient modes of a two-section induction heater of methodical action is formulated and solved. The results obtained provide a minimum of energy consumption for heating billets in transient modes under conditions of technological and energy constraints. Variants of starting the heater at various initial temperature states of the load are considered. The results of a comparative analysis of the eff ectiveness of the obtained control algorithms are presented. The structure of the power supply and control system of the induction heating complex is proposed.

Bioheat Transfer Basis of Human Thermoregulation: Principles and Applications

Thermoregulation is a process that is essential to the maintenance of life for all warm-blooded mammalian and avian species. It sustains a constant core body temperature in the face of a wide array of environmental thermal conditions and intensity of physical activities that generate internal heat. A primary component of thermoregulatory function is the movement of heat between the body core and the surface via the circulation of blood. The peripheral vasculature acts as a forced convection heat exchanger between blood and local peripheral tissues enabling heat to be conducted to the skin surface where is may be transferred to and from the environment via conduction, convection, radiation, and/or evaporation of water as local conditions dictate. Humans have evolved a particular vascular structure in glabrous (hairless) skin that is especially well suited for heat exchange. These vessels are called arteriovenous anastomoses (AVAs) and can vasodilate to large diameters and accommodate high flow rates. We report herein a new technology based on a physiological principle that enables simple and safe access to the thermoregulatory control system that allow manipulation of thermoregulatory function. The technology operates by applying a small amount of heating local to control tissue on the body surface overlying the cerebral spine that upregulates AVA perfusion. Under this action, heat exchangers can be applied to glabrous skin, preferably on the palms and soles, to alter the temperature of elevated blood flow prior to its return to the core. Therapeutic and prophylactic applications are discussed.

Magnetically propelled Carreau fluid flow over Penetrable Sensor Surface Influenced by Thermal Radiation, Joule Heating and Heat Generation

This examination emphasizes the analysis of thermal transmission of Carreau fluid flow on a permeable sensor surface equipped with radiation, Joule heating, internal heat source, and magnetic field. With the above effects and assumptions, the equations that administer the flow are formulated. Configured system of equations is productively reduced to system of ordinary differential equations. The reduced system is then dealt with the Runge-Kutta-Fehlberg 4th -5th order tool equipped by shooting technique. Derived numerical solutions are utilized to plot graphs and tables. The study concluded with some important findings such as power law index, thermal radiation parameter and heat source parameter enhance the thermal panel whereas Weissenberg number deescalates the same. The power law index and permeable velocity decrease the velocity panel significantly. Diagrammatic representation of streamlines of the flow has been given to strengthen the study. A detailed description has been produced about the results obtained in the study