Numerical simulation of thermal diamond filter for working station 1-5 of synchrotron “SKIF“

Numerical 3D-simulations of thermal loads of thermal diamond filter for the working station 1-5 of synchrotron “SKIF” has been performed. An efficient version of a water-cooling system of a CVD diamond by means of mini-channels in copper flanges with a total heat release power of 1290 W is presented. The influence of various configurations of the cooling system, different boundary conditions (thermal insulation, radiation heat exchange), water supply pressure on the maximum temperature in diamond wafer has been investigated. The influence of the temperature dependence of the properties of diamond glass has been studied. The maximum temperature on the diamond wafer is found to be 317.6 °C absorbing 1290 W of power correspond to the safe mode for some specific cooling system configuration. The corresponding flow rate of 7 °C cooling water was 13.1 l/min.

Optimal control of the radiation heat exchange equations for multi-component media

An analysis of optimal control problems for nonlinear elliptic equations modeling complex heat transfer with Fresnel conjugation conditions on the discontinuity surfaces of the refractive index is presented. Conditions for the solvability of extremal problems and the nondegeneracy of the optimality system are obtained. For the control problem with boundary observation, the bang-bang property is set.

THE SOOT OPTICAL PROPERTIES IN PREMIXED ACETYLENE/AIR FLAME MEASURED BY LASER-INDUCED INCANDESCENCE

Data on the optical properties of soot are necessary to calculate the amount of sunlight absorbed by nanoparticles in the atmosphere and on the surface of the ice. Such information is used for calculating the radiation heat exchange in combustion processes, assessing the quality of carbon black, and other applications. To date, a large amount of data on the optical properties of soot has been accumulated due to its importance in practical applications. However, a wide variation of soot's optical properties is observed under different formation conditions.

Application of Ultrasonic Guided Wave in LMPH Tube of Ethylene Cracking Furnace

LMPH (Radiation heat exchange tube), the key section of ethylene cracking furnace, has various failure behaviors (e.g., carbonation, vulcanization, oxidation, and deformation) because of its rigorous working conditions and complicated structure [1]. In this paper, the ultrasonic guided wave is applicable to inspect the interior and surface of the LMPH tube. The results demonstrate that large components in the similar structure of the heat exchange bent tube bundle can be inspected effectively, efficiently, conveniently, compared with the traditional inspection method. One inspection example of an ethylene cracking furnace tube bundle is forwarded. The paper also provides an engineering application/case and valuable crafting process for the detection of similar structures by the ultrasonic guided wave method.

Numerical modeling of radiation heat exchange in combustion chambers and heat exchangers of power installations

The application of numerical modeling is considered to solve the problems of radiation heat exchange in structurally inhomogeneous two-phase media which are realized during the combustion of fuel in boiler units atmospheric emissions from air carriers when they move at supersonic speeds. The optically active ingredients of the gas phase of the combustion products have a sharp selection of spectral absorption lines (radiation) which causes a difference in the spectral transmission functions for selective radiation from the spectral transmission functions for non-selective radiation (gray body). In the presence of a dispersed phase of the combustion products acute selection is subjected to such a parameter of the radiation propagation medium as the probability of quantum survival. The number of spectral lines determining the spectral transmission functions increases with temperature and is determined by hundreds of thousands of lines at high temperatures. In this paper we consider a closed simulation of radiation heat transfer in combustion chambers when the temperature field in the combustion chambers is calculated first and then the flux of thermal radiation to the tube heat-receiving surfaces.

Calculation of efficiency of work of converters of energy of solar heat and electric stations

The modeling of complex radiation heat exchange in the system “Sun-atmosphere-solar thermal and electric stations” is considered. The structural scheme of solar radiation inflows to the heat-absorbing surface of solar thermal and electrical stations is discussed. Calculations of spectral intensities and the flux of solar radiation, taking into account the selectivity of molecular absorption of radiation by the ingredients of the gas phase of the atmosphere, scattering and absorption of radiation by atmospheric aerosol and clouds, taking into account the statistics of their distribution depending on the location of the station and the time of year. Modeling of anthropogenic impacts on the operation of solar thermal and electrical stations in connection with the capture of anthropogenic emissions of sols by clouds is performed. An assessment of the impact of economic activity on the work of promising solar thermal and electrical stations. The developed methods for calculating the spectral intensities and fluxes of short-wave and long-wave radiation on the underlying surface make it possible to calculate the efficiency of the functioning of solar hot water supply systems for any location and structural solution.

Monitoring the Effective Ambient and Sky Temperature Based on Infrared Sensor for Advanced Thermal Calculations

Building performance simulations and advanced thermal analysis are becoming the basis for a well-established practice of a building sector. This approach requires many input data which are typically not available on site. Apart from already well-practiced climate variable quantities, such as ambient temperature, solar radiation and parameters of wind, more complex data are needed for advanced building thermal analysis. One of those is based on longwave radiation level. A pyrgeometer is a device that measures longwave radiation part of whole thermal radiation phenomena. This can be determined based on sky or effective ambient temperature monitoring. Secondly, both variables might be approximated by infrared sensors as an applicable option in the calculation of longwave radiation heat exchange between the external surface and the ambient building environment. The paper presents data obtained both by pyrgeometer and infrared sensor corresponding to their mutual comparison to demonstrate its application when longwave radiation exchange needs to be calculated or analyzed in advanced. Integrating of the infrared sensor with aim to monitor the effective ambient and/or sky temperature enables its applicability as an alternative, integrated and less cost consuming method towards the monitoring by commercial pyrgeometer.