Heat exchange in annular channel with intermediate heat carrier

1983 ◽  
Vol 44 (4) ◽  
pp. 443-446
Author(s):  
V. A. Dement'ev
1985 ◽  
Vol 21 (10) ◽  
pp. 479-481
Author(s):  
A. I. Mumladze ◽  
G. R. Khalitova ◽  
E. K. Vachagina ◽  
Yu. G. Nazmeev

1984 ◽  
Vol 46 (2) ◽  
pp. 130-133
Author(s):  
A. A. Mikhalevich ◽  
V. A. Nemtsev ◽  
V. I. Nikolaev ◽  
L. N. Shegidevich

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Cheng Li ◽  
Wei-Jun Zhang ◽  
Zhi Yi ◽  
Na Li ◽  
Kai Li

Intermediate heat carriers have been applied in engineering as enhanced heat transfer elements, but their theoretical analysis still needs to be improved. Therefore, an intermediate heat carrier is added to establish the quaternary model of the furnace gas under nongray radiation characteristics. Based on this model, an analytical expression of heat flux on the surface of the billet is derived. General rule of the impact of intermediate heat carrier on the thermal efficiency in the furnace can be properly derived by analytical calculation from a theoretical point of view. The results show that the longer the length of the intermediate heat carrier located at the top of the furnace, the greater the heat exchange capacity on the surface of the billet. Meanwhile, when the intermediate heat carrier is located in the center of the furnace top, the billet gets higher heat flux; the closer to both sides, the lower the heat flux. In addition, the influence that the surface emissivity of the intermediate heat carrier has on the heat transfer of the billet surface is related to the values of εg and αgw. Comparison with previous literature shows that adding intermediate heat carrier can improve the heat exchange capacity of billet.


2020 ◽  
Vol 22 (4) ◽  
pp. 82-93
Author(s):  
Roman Chernukhin ◽  
◽  
Aleksey Dolgushin ◽  
Nikolai Kasimov ◽  
Vladimir Ivancivsky ◽  
...  

Introduction. Machines and equipment in its composition may contain hydraulic systems to ensure the functioning of the main and auxiliary systems. It is known that a common disadvantage of hydraulic systems and drives is the dependence of the viscosity of the applied fluids on temperature. A noticeable part of technological machines and equipment is located in unheated or poorly heated industrial premises and a change in the viscosity of working fluids with a decrease in the ambient temperature can significantly affect the parameters of technological processes. An important factor in ensuring the stability of the technological processes parameters is the degree of preparation of machines and equipment for operation at low temperatures or in conditions of fluctuating temperature conditions. In this regard, the question arises of ensuring the required temperature of technical fluids before turning on machines and equipment, and maintaining the required thermal regime during the operation of its units and assemblies. One way to solve this problem is to use external heat sources. Various heat exchange devices can serve as such sources. In the heat exchange device, the heat carrier is heated, which is then fed into the heat exchange jacket of the machinery and equipment units. Both liquid and gaseous media are used to heat the coolant in the heat exchanger. In the latter case, the heat exchanger is called a recuperator. The efficiency of the recuperator is determined by its design and flow characteristics. There are methods for the analytical determination of both the design and flow characteristics of the recuperator, but these methods are quite laborious. The use of computer simulation of thermal processes makes it possible to successfully solve the calculation problem, and also significantly reduces the design time of heat exchangers. The aim of the work is to substantiate the flow characteristics of the recuperator for maintaining the thermal regime through computer simulation. The research method is computer simulation of thermal processes, which is implemented using the SolidWorks software package from Dassault Systems and its Flow Simulation application for simulating thermal processes in scientific research and engineering. Results and discussion. Simulation carried out in stationary and non-stationary modes made it possible to determine the effect of pump performance on the temperature of the coolant at the outlet of the recuperator. It is found that when the heat carrier flow rate is more than 20 l/h, its temperature does not reach the required values, despite the fact that the gases leaving the recuperator have a significant residual temperature. The efficiency of the recuperator is assessed by determining the exergy efficiency. Based on the data obtained, the most preferable are the pump productivity values lying in the range from 4 to 20 l/h.


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