Research of Vacuum Degree Influence on Performance of Vacuum Heat Insulation Oil Pipe

2013 ◽  
Vol 732-733 ◽  
pp. 172-175
Author(s):  
Zhong Hua Wang ◽  
Hai Qian Zhao

In this paper, mathematical model for heat transfer in thermal barrier is established based on the experiment which tested apparent heat conductivity of heat insulation oil pipes. Vacuum degree influence on performance of vacuum heat insulation oil pipe is analyzed by contrasting heat insulation oil pipes in different grades. The main conclusions are as follow. When internal pressure in the thermal barrier is between 0~20Pa or greater than 40Pa, the apparent heat conductivity increases with the pressure. And when internal pressure in the thermal barrier is between 20~40Pa, the apparent heat conductivity decreases with the pressure in volatility. When internal pressure in the thermal barrier is between 30~40Pa, the apparent heat conductivity of heat insulation oil pipe is lesser.

2008 ◽  
Vol 6 ◽  
pp. 205-209
Author(s):  
V.Sh. Shagapov ◽  
R.R. Urazov

The flow of wet natural gas in the pipeline is considered in the presence of the formation of gas hydrates on the internal walls of the channel. In the description of the phenomenon, such interrelated processes as phase transformations and mass transfer of water into the composition of gas hydrates, heat transfer between the gas stream and the environment, heat conductivity in the ground are taken into account.


2013 ◽  
Vol 732-733 ◽  
pp. 238-241
Author(s):  
Zhong Hua Wang

Influences of void ratio of glass fiber cloth, conductivity of glass fiber cloth, number of of insulation layer and emissivity of aluminium foil on apparent heat conductivity of vacuum heat insulation oil pipe are calculated based on the experiment plat in master machinery plant of Liaohe Petroleum Exploration Bureau. The results show that apparent heat conductivity of vacuum heat insulation oil pipe is inverse ratio to void ratio of glass fiber cloth, and is proportional to conductivity of glass fiber cloth and emissivity of aluminium foil. At vacuum condition, 6 layers is appropriate.


Author(s):  
O. A. Kabov ◽  
I. V. Marchuk ◽  
J. C. Legros

A mathematical model for vapor condensation in cylindrical longitudinally finned minichannel has been proposed taking into account all temperature non-uniformity. The model describes annular and rivulet flow regimes until complete grooves flooding. It is shown that when the model does not account for the wall heat conductivity the maximal calculated enhancement of heat transfer is predicted for the “sharp” trapezoidal fins. The most enhanced heat transfer in the case of non-isothermal fins has been obtained for the curvilinear fins of expanded Adamek’s parametric family. When reducing the heat conductivity the curvilinear fins become still more effective in comparison with the trapezoidal fins. The wall non-isothermity is a factor, which cannot be neglected when modeling condensation in a minichannels with finned surfaces.


2020 ◽  
Vol 786 (11) ◽  
pp. 30-34
Author(s):  
A.M. IBRAGIMOV ◽  
◽  
L.Yu. GNEDINA ◽  

This work is part of a series of articles under the general title The structural design of the blast furnace wall from efficient materials [1–3]. In part 1, Problem statement and calculation prerequisites, typical multilayer enclosing structures of a blast furnace are considered. The layers that make up these structures are described. The main attention is paid to the lining layer. The process of iron smelting and temperature conditions in the characteristic layers of the internal environment of the furnace is briefly described. Based on the theory of A.V. Lykov, the initial equations describing the interrelated transfer of heat and mass in a solid are analyzed in relation to the task – an adequate description of the processes for the purpose of further rational design of the multilayer enclosing structure of the blast furnace. A priori the enclosing structure is considered from a mathematical point of view as the unlimited plate. In part 2, Solving boundary value problems of heat transfer, boundary value problems of heat transfer in individual layers of a structure with different boundary conditions are considered, their solutions, which are basic when developing a mathematical model of a non-stationary heat transfer process in a multi-layer enclosing structure, are given. Part 3 presents a mathematical model of the heat transfer process in the enclosing structure and an algorithm for its implementation. The proposed mathematical model makes it possible to solve a large number of problems. Part 4 presents a number of examples of calculating the heat transfer process in a multilayer blast furnace enclosing structure. The results obtained correlate with the results obtained by other authors, this makes it possible to conclude that the new mathematical model is suitable for solving the problem of rational design of the enclosing structure, as well as to simulate situations that occur at any time interval of operation of the blast furnace enclosure.


2021 ◽  
Vol 1 (2) ◽  
pp. 12-20
Author(s):  
Najmeh Keshtkar ◽  
Johannes Mersch ◽  
Konrad Katzer ◽  
Felix Lohse ◽  
Lars Natkowski ◽  
...  

This paper presents the identification of thermal and mechanical parameters of shape memory alloys by using the heat transfer equation and a constitutive model. The identified parameters are then used to describe the mathematical model of a fiber-elastomer composite embedded with shape memory alloys. To verify the validity of the obtained equations, numerical simulations of the SMA temperature and composite bending are carried out and compared with the experimental results.


1989 ◽  
Vol 12 (9) ◽  
pp. 1187 ◽  
Author(s):  
M.I. Ismail ◽  
A.S.A. Ammar ◽  
M. El-Okeily

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