scholarly journals Mathematical Modeling Of Heat Transfer in the System “The Object Of Heating – Thermal Insulation Layer – The External Environment” and Microclimate Parameters of Industrial Premises

2016 ◽  
Vol 72 ◽  
pp. 01118
Author(s):  
M. A. Ulchiekov
2011 ◽  
Vol 90-93 ◽  
pp. 3057-3060 ◽  
Author(s):  
Jian Jun Liu ◽  
Gui Hong Pei ◽  
You Jun Ji

Steam stimulation is one of the main methods used in heavy oil reservoir development. How to inject high temperature and high dryness steam is a key factor to enhance heavy oil recovery. It is significant to evaluate heat transfer of steam pipeline and optimize thermal insulation layer for heavy oil exploitation. Based on fluid mechanics, heat transfer theory, considered phase change, mathematical model to calculate heat transfer and heat loss of steam pipeline was derived. Using COMSOL Multiphysics, a finite element based program for simulating unlimited multiphysics and single physics applications, the author simulated heat transferring in ground steam pipeline and analyzed the effect of thermal insulation layer. From the simulation results, it was known that, (1) Along with the pipeline distance increases, the steam dryness decreases, the decrease rate decreases with the distance increases. (2) At the same transmission distance, the bigger the thermal insulation layer thickness is, the smaller the heat loss of the steam is. The heat loss of steam transmission mainly center on the first half pipeline. (3) With the thickness of thermal insulation layer increases, the heatloss declines. After the thickness of thermal insulation layer increases 90 mm, increasing the thickness has no obvious effect on reducing the heat loss. So, it is suggested that the thermal insulation layer thickness should be 75-80mm.


2017 ◽  
pp. 178-178
Author(s):  
Yuan Zhang ◽  
Zhijun Wan ◽  
Zhaoyang Ma ◽  
Bin Gu ◽  
Yangsheng Ma

2017 ◽  
Vol 7 (2) ◽  
pp. 22-26
Author(s):  
Igor G. BELYAKOV

Mathematical modeling of process of nonstationary heat transfer through walling exploited in intermitt ent heating conditions is viewed. Analytical dependence is revealed for fi nding of maximum permissible thickness of heat insulation layer providing required heating time. Based on this procedure the results of calculation of outer walls diff erent variants are presented. Comparative analysis of heating time of walling insulated with sandless coarse-porous expanded clay concrete.


2016 ◽  
Vol 824 ◽  
pp. 445-452
Author(s):  
Ivan Chmúrny

The value of the external surface resistance on the outside of the structure in the summer season affects the energy need for cooling buildings. The paper analyzes the convection and radiation in the external environment for the current climate conditions of Slovakia in terms of their impact on the value of the external surface resistance to heat transfer in the months when it is expected cooling of buildings. Analysis of the external surface resistance to heat transfer on the outside of the structure for the monthly method of calculating the energy need for heating and cooling.


2021 ◽  
Vol 4 (3) ◽  
pp. 5-22
Author(s):  
S. Plehanova ◽  
N. Vingradova

the possibility of obtaining structural and thermal insulation foam concrete of non-autoclave hardening with improved construction and technical characteristics for the device of a thermal insulation layer in the con-struction of road pavement due to three-dimensional dispersed reinforcement with polypropylene fiber is theoretically justified and experimentally confirmed. Based on the results of studies of the influence of technological factors on the properties of foam concrete, the optimal content (up to 0.25% of the cement mass) and the length (12 mm) of reinforcing polypropylene fibers have been established, which allows ob-taining high strength indicators of dispersed-reinforced cement stone for bending (an increase of 12-20%) and compression (an increase of 6-12%) compared with non-reinforced cement stone of non-autoclaved foam concrete. The analysis of the process of structure formation of dispersed reinforced foam concrete from the standpoint of a systematic approach based on multifactorial polynomial models of the influence of the ratio of filler and binder, as well as the number of dispersed reinforcing fibers, which is determined by the optimal conditions for the distribution of solid and gas phases, as well as the reinforcement of adjacent interstitial partitions of foam concrete, linking them into one asociate, which ensures the joint work of the material under various external influences. A method was developed to increase the durability of the road surface and eliminate the influence of the frost heaving effect on the quality of the road surface by intro-ducing the necessary amount of effective thermal insulation layer into the road surface design. The analysis of the regularity of the heat transfer process in the soil mass of the roadbed and multilayer road pavement is carried out. Based on the analysis, the values of the necessary resistance to heat transfer of road pavement for the natural and climatic regions of the country are determined and a method for calculating the value of the thermal insulation (frost-proof) layer of road pavement is proposed. A method was developed for calcu-lating the value of the thermal insulation layer using monolithic fibre foam concrete and a nomogram to de-termine the required value of the thermal insulation layer made of monolithic non-autoclaved structural and thermal insulation fibre foam concrete of classes D600-D1000.


2014 ◽  
Vol 35 (1) ◽  
pp. 117-140 ◽  
Author(s):  
Andrzej Witkowski ◽  
Mirosław Majkut ◽  
Sebastian Rulik

Abstract A commercially available ASPEN PLUS simulation using a pipe model was employed to determine the maximum safe pipeline distances to subsequent booster stations as a function of carbon dioxide (CO2) inlet pressure, ambient temperature and ground level heat flux parameters under three conditions: isothermal, adiabatic and with account of heat transfer. In the paper, the CO2 working area was assumed to be either in the liquid or in the supercritical state and results for these two states were compared. The following power station data were used: a 900 MW pulverized coal-fired power plant with 90% of CO2 recovered (156.43 kg/s) and the monothanolamine absorption method for separating CO2 from flue gases. The results show that a subcooled liquid transport maximizes energy efficiency and minimizes the cost of CO2 transport over long distances under isothermal, adiabatic and heat transfer conditions. After CO2 is compressed and boosted to above 9 MPa, its temperature is usually higher than ambient temperature. The thermal insulation layer slows down the CO2 temperature decrease process, increasing the pressure drop in the pipeline. Therefore in Poland, considering the atmospheric conditions, the thermal insulation layer should not be laid on the external surface of the pipeline.


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