scholarly journals Invariant Imbedding and the Radiation Transfer in a Plane-Parallel Inhomogeneous Atmosphere

2014 ◽  
Vol 2014 ◽  
pp. 1-9
Author(s):  
Arthur G. Nikoghossian

The invariant imbedding technique is applied to the problems of radiation transfer in a plane-parallel inhomogeneous atmosphere. All the parameters which describe the elementary event of scattering and the distribution of the energy sources are allowed to vary with depth. Mathematically, the considered standard problems of the theory are reduced to initial-value problems which are better adapted to capabilities of the modern high speed computers. The reflectance of an atmosphere is shown to play a prominent role in describing the diffusion process since all the other characteristics of the radiation field are expressed through it. Three transfer problems frequently encountered in astrophysical applications are discussed: the radiation diffusion in the source-free medium, in a medium with arbitrarily distributed energy sources, as well as the problem of finding the statistical mean quantities, characteristics of the multiple scattering in the atmosphere.

2007 ◽  
Vol 43 (1) ◽  
pp. 167-169 ◽  
Author(s):  
J. Mankowski ◽  
J. Dickens ◽  
M. Giesselmann ◽  
B. McDaniel ◽  
B. McHale ◽  
...  

Author(s):  
Petro Lezhnyuk ◽  
Iryna Hunko ◽  
Juliya Malogulko ◽  
Iryna Kotylko ◽  
Lіudmyla Krot

Urgency of the research. Current trends of distributed generation development in Ukraine indicate a rapid generation in-crease from renewable energy plants. Most developed countries gradually refuse from the fossil fuels use and invest more and more to the “green” energy. Therefore, there is a need for a detailed study of the operation conditions of distributed energy sources due to their instability, as well as the processes that arise in distribution electric networks with diverse types of distributed energy sources. Target setting. In the producing process of power energy by distributed energy sources due to the increase in their num-ber, there are situations where several renewable sources of energy operate to only one system of buses. Thus, such distributive networks acquire the features of a local power system, which complicates the control process of such systems, and also there is a problem with the electricity supply of consumers. Actual scientific researches and issues analysis. The analysis of publications suggests that in literature more attention is paid to studying the operating modes of solar power plants, or small hydroelectric power plants. However, almost no attention was paid to the study of their cooperation work. Uninvestigated parts of general matters defining. Only a few works are devoted to the study of the cooperation of the diverce sources of distributed energy sources in the local electrical systems. That is why, their impact on power distribution networks and on the grid in general has not been studied extensively. The research objective. In this article was considered the influence of asynchronous generators on small hydroelectric power plants on the operation modes of distribution electrical networks, and were investigated the processes that are occurring in local power systems with different types of distributed energy sources. The statement of basic materials. Based on the research results, was developed a computer model of a such system in the PS CAD software environment. Two solar stations and one small hydroelectric power station with an asynchronous generator were connected to the power supply. It was shown the simulation of two modes of operation: a joint operation of a small hydroelectric power station, two solar power stations and a power supply center; a joint operation of a small hydroelectric pow-er plant, two solar power stations and a power supply disconnected. Conclusions. As a result of computer simulation, it is shown that by switching on a small hydroelectric power plant with an asynchronous generator in the case of an emergency shutdown of centralized power supply, it is possible to restore the work of solar power plants, and thus partially or completely restore the power supply of consumers.


2021 ◽  
Vol 2039 (1) ◽  
pp. 012027
Author(s):  
S A Perminov ◽  
E V Lipnyagov ◽  
M A Parshakova

Abstract The effect of a low-boiling impurity (CO2 gas <1.5% mol) on the kinetics of boiling-up of superheated n-pentane in a vertical glass tube have been studied by high-speed video (2050 fps). The method of continuous pressure decrease from 2.00 to 0.10 MPa (in the temperature range of 100.2-145.1 °C), as well as the method of measuring the lifetimes of superheated liquids at 0.10 MPa (90.2-134.1 °C) have been used. The inner surface of the tube has two visible defects, one of which defines the boundary of the attainable superheat. After degassing the system, the defects of tube cease to play an appreciable role, the active centers are redistributed. The temperature of the attainable superheat increases from the initial value by 20 °C in tests with gas and by 10 °C in subsequent tests without it. The result obtained may be related to physical gas adsorption on the glass surface during the process of evacuation of the system.


Author(s):  
Valeriy Kharchenko ◽  
Valentin Gusarov ◽  
Vadim Bolshev

Using microgrid generation technologies is proposed in order to organize reliable power supply to rural areas. The concept of microgrid based on RES is considered as one of the realization forms of the distributed energy paradigm. In this chapter, there are the principles of generating complex formation in any given microgrid considering the specifics of the region, consumption patterns, and the potential of renewable energy sources in a given area. The algorithm for meeting the challenges of forming the structure of the microgrid generating structure is shown. The criteria for selection of power generation sources when solving the issue of their inclusion in the microgrid is proposed. The chapter also suggests the design of the micro gas turbine that is able to operate on biogas.


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