Space engineering. Calculation of radiation and its effects and margin policy handbook

2021 ◽  
Keyword(s):  
Engineering Calculation

Calculation And Experimental Substantiation Of Optimal Design Of The Welded Joint Of Plates On Соver Plates

2020 ◽  
pp. 17-24
Keyword(s):  
Welded Joint ◽  
Experimental Studies ◽  
Engineering Calculation ◽  
Tensile Tests ◽  
Physical Nonlinearity ◽  
Steel Plates ◽  
Optimal Parameters ◽  
Actual Problem ◽  
Numerical Research ◽  
Cover Plates

The article is devoted to the actual problem of assigning optimal parameters for connecting steel plates on cover plates with angular welds that are widely used in construction practice. The article presents the results of a comprehensive study of operation of a welded assembly of the plates connection on cover plates. An algorithm is proposed for determining the optimal parameters of a welded joint with fillet welds on the cover plates, which makes it possible to obtain a strength balanced connection. The results of full-scale tensile tests of models were presented. These results confirmed the correctness of the assumed design assumptions, and made it possible to obtain a form of destruction, not characteristic and not described in the normative literature, expressed by cutting the main elements along the length of the overlap in the joint. The possibility of such a form of destruction was confirmed by the results of numerical research in a nonlinear formulation. The optimal parameters of the nodal welded joint determined by engineering calculation are confirmed by experimental studies, as well as by the results of numerical experiments on models of calculation schemes, taking into account the physical nonlinearity of the material operation. The obtained dependence for determining the bearing capacity of the joint by the cut-off mechanism and the expression for limiting the overlap length of the cover plates will make it possible to predict the nature of the fracture and design equally strong joints.

An Engineering Calculation Method for Multi-Component Stagnant Droplet Evaporation With Finite Diffusivity

1994 ◽  
Author(s):  
J. S. Chin
Keyword(s):  
Heat Transfer ◽  
Diffusion Coefficient ◽  
Liquid Phase ◽  
Vapor Pressure ◽  
Molecular Mass ◽  
Calculation Method ◽  
Engineering Calculation ◽  
Droplet Evaporation ◽  
Diffusion Resistance ◽  
Distillation Curve

A practical engineering calculation method has been formulated for commercial multicomponent fuel stagnant droplet evaporation with variable finite mass and thermal diffusivity. Instead of solving the transient liquid phase mass and heat transfer partial differential equation set, a totally different approach is used. With zero or infinite mass diffusion resistance in liquid phase, it is possible to obtain vapor pressure and vapor molecular mass based on the distillation curve of these turbine fuels. It is determined that Peclet number (Pef) is a suitable parameter to represent the mass diffusion resistance in liquid phase. The vapor pressure and vapor molecular mass at constant finite Pef is expressed as a function of finite Pef, vapor pressure, and molecular mass at zero Pef and infinite Pef. At any time step, with variable finite Pef, the above equation is still valid, and PFsPef=∞, PFsPef=0, MfvPef=∞, MfvPef=0 are calculated from PFsPef≡∞, PFsPef≡0, MfvPef≡∞, MfvPef≡0, thus PFs and Mfv can be determined in a global way which eventually is based on the distillation curve of fuel. The explicit solution of transient heat transfer equation is used to have droplet surface temperature and droplet average temperature as a function of surface Nusselt number and non-dimensional time. The effect of varying com position of multi-component fuel evaporation is taken into account by expressing the properties as a function of molecular mass, acentric factor, critical temperature, and critical pressure. A specific calculation method is developed for liquid fuel diffusion coefficient, also special care is taken to calculate the binary diffusion coefficient of fuel vapor-air in gaseous phase. The effect of Stefan flow and natural convection has been included. The predictions from the present evaporation model for different turbine fuels under very wide temperature ranges have been compared with experimental data with good agreement.

Development of an Evaporating Type Air Cooler for Ventilation Systems

2021 ◽  
pp. 37-44
Author(s):  
А. В. Бараков ◽  
В. Ю. Дубанин ◽  
Д. А. Прутских ◽  
А. А. Надеев
Keyword(s):  
Experimental Studies ◽  
Engineering Calculation ◽  
Design Calculation ◽  
Efficiency Coefficient ◽  
Empirical Relationships ◽  
Additional Energy ◽  
Air Cooler ◽  
Hot Season ◽  
Experimental And Theoretical Studies ◽  
Ventilation Systems

Постановка задачи. Подаваемый в помещения воздух в жаркое время года должен быть охлажден до комфортных температур. В связи с тем, что дополнительного расхода энергии на это охлаждение не предусмотрено, возможно применить воздухоохладитель испарительного типа. Однако известные в настоящее время результаты экспериментальных и теоретических исследований таких аппаратов не позволяют их проектировать, что препятствует их распространению. Рассмотрено строение такого аппарата и выполнены его теоретические и экспериментальные исследования, результаты которых могут быть использованы для инженерного расчета и конструирования подобных аппаратов. Результаты. Описан сконструированный авторами воздухоохладитель испарительного типа для систем вентиляции. Проведено теоретическое и экспериментальное исследование воздухоохладителя. Получены аналитические соотношения для определения времени движения насадки в «мокрой» камере аппарата, температуры охлажденного воздуха и температуры насадки в любом сечении контура циркуляции. Получены эмпирические соотношения для коэффициента эффективности охладителя и его гидравлического сопротивления. Выводы. Полученные зависимости послужат основой для разработки методики проектного расчета воздухоохладителей косвенно-испарительного типа с перемещающимся псевдоожиженным слоем в поле центробежных сил. Statement of the problem. The air supplied to the premises during the hot season must be cooled to comfortable temperatures. Due to the fact that additional energy consumption for this cooling is not provided, it is possible to use an evaporative-type air cooler. However, the currently known results of experimental and theoretical studies of such devices do not allow for their design, which prevents their spread. The structure of such an apparatus is considered and its theoretical and experimental studies are carried out, the results of which can be used for engineering calculation and design of such apparatus. Results. An evaporative-type air cooler designed by the authors for ventilation systems is described. A theoretical and experimental study of the air cooler has been carried out. Analytical relationships were obtained for determining the time of movement of the material checker in the «wet» chamber of the apparatus, the temperature of the cooled air and the temperature of the checker in any section of the circulation loop. Empirical relationships have been obtained for the efficiency coefficient of the cooler and its hydraulic resistance. Сonclusions. The obtained dependencies will serve as the basis for the development of a methodology for the design calculation of indirect-evaporative air coolers with a moving fluidized bed in the field of centrifugal forces.

scholarly journals Characteristics and Practices of Ecological Flow in Rivers with Flow Reductions Due to Water Storage and Hydropower Projects in China

Water ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 1091 ◽  
Author(s):  
Lejun Ma ◽  
Xingnan Zhang ◽  
Huan Wang ◽  
Changjun Qi
Keyword(s):  
Calculation Method ◽  
River Flow ◽  
Water Storage ◽  
Engineering Calculation ◽  
Water Diversion ◽  
Western China ◽  
Flow Management ◽  
Riverine Ecosystems ◽  
Management Scheme ◽  
Ecological Flow

Water and flow reductions in the channels downstream of water storage and hydropower projects have significant impacts on aquatic ecosystems. Understanding and analyzing the ecosystem status is of great significance to facilitate the protection of riverine ecosystems. A database was established based on the 2000–2017 environmental impact assessment (EIA) reports on water storage and hydropower projects in China, and corresponding analysis software was built based on an ArcGIS spatial analysis platform. The projects in China are mainly found in the Yangtze and Pearl River basins and in south-western China. The hydropower projects have a larger influence than the water storage projects on the flow of downstream rivers sections, and most of the hydropower projects, especially the water diversion projects, cause flow reductions in the downstream rivers. An ecological flow management mechanism in China implemented in 2006 provided a promising method to alleviate river flow reductions. However, there is still only one kind of ecological flow calculation method and few ecological flow regulation measures in use. Based on the advantages and problems of the existing ecological flow management system, this paper proposes a management scheme based on a regional-engineering calculation method. The results can facilitate decision making in ecological flow management.

Based on Estimation of the Ionospheric Characteristics HF Frequency Prediction Method

2012 ◽  
Vol 190-191 ◽  
pp. 936-939
Author(s):  
Chao Li ◽  
Yun Jiang Liu ◽  
Heng Yang Zhang ◽  
Xiao Peng Yang ◽  
Feng Wang
Keyword(s):  
Calculation Method ◽  
Prediction Method ◽  
Engineering Calculation ◽  
International Telecommunication Union ◽  
International Telecommunication ◽  
Time Availability ◽  
Hf Channel

To grasp Complex characteristics of shortwave (HF) channel is the key and difficulty to research HF communication. On the premise of comprehending the ionosphere prediction method in the Asia Oceania region, HF frequency prediction method recommended by the International Telecommunication Union (ITU) is improved in this paper, and the engineering calculation method of predicting HF frequency in the Asia Oceania region is concluded and summarized. Comparing with the ITS (the Institute for Telecommunication Science) software’s predicting result, the method is improved to some extent in time availability and SNR in the receiving point.

scholarly journals Finite element analysis of microclimate parameters in the metallurgical crane cabin

2021 ◽  
pp. 10-20
Author(s):  
V. V. Maslenskiy ◽  
◽  
Yu. I. Bulygin ◽  
Keyword(s):  
Finite Element ◽  
Air Conditioning ◽  
Engineering Calculation ◽  
Air Pressure ◽  
The Finite Element Method ◽  
Air Flow Rate ◽  
Ansys Software ◽  
Element Analysis ◽  
Air Conditioning System ◽  
Characteristic Points

Introduction. The article analyzes the microclimate parameters (temperature, speed and air pressure) in the metallurgical crane cabin provided by the air conditioning system using the finite element method integrated into the ANSYS software package. The metallurgical crane cabin air conditioning system was selected based on the engineering calculation of the required air flow rate supply, taking into account factors that affect the system performance, such as the location of the equipment and the degree of its dustiness. Problem Statement. The purpose of this research was to check the efficiency of the air conditioning system of the metallurgical crane cabin, which was selected based on the results of the engineering calculations. Theoretical Part. In the main part of the research, the distribution fields of temperature, speed and air pressure inside the cabin of a metallurgical crane were constructed, the values at the points of which were compared with the hygienic standards. In addition, the factors that affect the adequacy of the developed model were considered, namely the grid structure, the way to set the initial and boundary conditions. Conclusion. The refinement of the analysis grid and the consideration of infiltration in the model eventually allowed us to get more correct results: the temperature at the characteristic points differ by no more than 1.3 °C, the speed values do not exceed the standard 0.3 m/s, the average normalized temperature of 24 °C is maintained in a volume of about 60-70 % of the total cabin volume.

scholarly journals Methodology for the engineering calculation of flaps on Wind Turbines using BEM codes

2016 ◽  
Author(s):  
Maria Aparicio-Sanchez ◽  
Alvaro Gonzalez-Salcedp ◽  
Sugoi Gomez-Iradi ◽  
Xabier Munduate
Keyword(s):  
Three Dimensional ◽  
Unsteady Aerodynamics ◽  
Engineering Calculation ◽  
Root Effect ◽  
Validation And Verification ◽  
Momentum Theory ◽  
Aerodynamic Control ◽  
Control Devices ◽  
Circulation Theory ◽  
Blade Element

Abstract. Aeroelastic codes based on Blade Element Momentum theory are the standard used by many wind turbine designers. These codes usually include models and corrections for unsteady aerodynamics, tip and root effect, tower shadow and other effects. In general, this kind of codes does not include models to adequately simulate aerodynamic control devices. This paper presents a method to take into account the unsteady contributions due to the flap motion (based on indicial models) and the spanwise effects (based on circulation theory), in order to simulate flaps on the blades. This method can be included in BEM codes in general and it could also be applied to another kind of control devices. The validation and verification show the accuracy of this method using experimental data for two-dimensional unsteady cases, and CFD for three-dimensional steady and unsteady cases.

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