Studied on Return Water Temperature of Buried Pipe and Soil Temperature Field of Soil-Source Heat Hump System by the Finite-Element Method

2010 ◽  
Vol 171-172 ◽  
pp. 163-166
Author(s):  
Guo Dan Liu ◽  
Fu Sheng Liu ◽  
Dan Meng ◽  
Xu Quan Li ◽  
Zhi Gang Shi ◽  
...  

Heat transfer model of buried pipe heat exchanger is established first, and solved by the ANSYS finite element simulation software. Model is verified by experiment, average error is 6.4%. On the above basis, return water temperature of buried pipe and soil temperature are analyzed during whole operation. Through whole cooling season, outlet water temperature of buried pipe increased by 6.7°C, up to 21.2°C. After 45 days on transition season, temperature reduced 3.2°C, up to 18°C. Within one year, temperature difference is above 1.1°C before-and-after heating and cooling operation. It reveals that soil temperature cannot fully recover only by natural heat conduction and soil heat storage appears, which should be paid more attention in the project.

2020 ◽  
Vol 24 (5 Part B) ◽  
pp. 3357-3365
Author(s):  
Jingyun Jia ◽  
Xiaolong Zou ◽  
Xiantao Chen ◽  
Haibin Wang ◽  
Qiang Sun

To promote the full combustion efficiency of a body cremation furnace during cremation, the temperature and velocity of cremation furnace in the process of body combustion are simulated by finite element model. Firstly, the simplified finite element analysis model of cremation furnace and its finite element software is introduced in this study, and then the flow model, heat transfer model, and combustion model needed in the heat transfer process are described. According to the requirements of the finite element model, the mesh generation process of the cremation furnace model and the numerical solution method are presented. Finally, the model used in this study is verified by the test and simulation results. The results show that the method is reliable. Besides, the design parameters of the temperature part and the combustion speed part of the furnace under six different working conditions are analyzed to further optimize the structure of the furnace. The results of this study provide a good theoretical basis for cremation equipment and promote the development of China?s cremation industry.


Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2690
Author(s):  
Bo Pan ◽  
Xuguang Wang ◽  
Zhenyang Xu ◽  
Lianjun Guo ◽  
Xuesong Wang

The Split Hopkinson Pressure Bar (SHPB) is an apparatus for testing the dynamic stress-strain response of the cement mortar specimen with pre-set joints at different angles to explore the influence of joint attitudes of underground rock engineering on the failure characteristics of rock mass structure. The nuclear magnetic resonance (NMR) has also been used to measure the pore distribution and internal cracks of the specimen before and after the testing. In combination with numerical analysis, the paper systematically discusses the influence of joint angles on the failure mode of rock-like materials from three aspects of energy dissipation, microscopic damage, and stress field characteristics. The result indicates that the impact energy structure of the SHPB is greatly affected by the pre-set joint angle of the specimen. With the joint angle increasing, the proportion of reflected energy moves in fluctuation, while the ratio of transmitted energy to dissipated energy varies from one to the other. NMR analysis reveals the structural variation of the pores in those cement specimens before and after the impact. Crack propagation direction is correlated with pre-set joint angles of the specimens. With the increase of the pre-set joint angles, the crack initiation angle decreases gradually. When the joint angles are around 30°–75°, the specimens develop obvious cracks. The crushing process of the specimens is simulated by LS-DYNA software. It is concluded that the stresses at the crack initiation time are concentrated between 20 and 40 MPa. The instantaneous stress curve first increases and then decreases with crack propagation, peaking at different times under various joint angles; but most of them occur when the crack penetration ratio reaches 80–90%. With the increment of joint angles in specimens through the simulation software, the changing trend of peak stress is consistent with the test results.


Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3298
Author(s):  
Gianpiero Colangelo ◽  
Brenda Raho ◽  
Marco Milanese ◽  
Arturo de Risi

Nanofluids have great potential to improve the heat transfer properties of liquids, as demonstrated by recent studies. This paper presents a novel idea of utilizing nanofluid. It analyzes the performance of a HVAC (Heating Ventilation Air Conditioning) system using a high-performance heat transfer fluid (water-glycol nanofluid with nanoparticles of Al2O3), in the university campus of Lecce, Italy. The work describes the dynamic model of the building and its heating and cooling system, realized through the simulation software TRNSYS 17. The use of heat transfer fluid inseminated by nanoparticles in a real HVAC system is an innovative application that is difficult to find in the scientific literature so far. This work focuses on comparing the efficiency of the system working with a traditional water-glycol mixture with the same system that uses Al2O3-nanofluid. The results obtained by means of the dynamic simulations have confirmed what theoretically assumed, indicating the working conditions of the HVAC system that lead to lower operating costs and higher COP and EER, guaranteeing the optimal conditions of thermo-hygrometric comfort inside the building. Finally, the results showed that the use of a nanofluid based on water-glycol mixture and alumina increases the efficiency about 10% and at the same time reduces the electrical energy consumption of the HVAC system.


Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 833
Author(s):  
Irene Mirandola ◽  
Guido A. Berti ◽  
Roberto Caracciolo ◽  
Seungro Lee ◽  
Naksoo Kim ◽  
...  

This research provides an insight on the performances of machine learning (ML)-based algorithms for the estimation of the energy consumption in metal forming processes and is applied to the radial-axial ring rolling process. To define the mutual influence between ring geometry, process settings, and ring rolling mill geometries with the resulting energy consumption, measured in terms of the force integral over the processing time (FIOT), FEM simulations have been implemented in the commercial SW Simufact Forming 15. A total of 380 finite element simulations with rings ranging from 650 mm < DF < 2000 mm have been implemented and constitute the bulk of the training and validation datasets. Both finite element simulation settings (input), as well as the FI (output), have been utilized for the training of eight machine learning models, implemented with Python scripts. The results allow defining that the Gradient Boosting (GB) method is the most reliable for the FIOT prediction in forming processes, being its maximum and average errors equal to 9.03% and 3.18%, respectively. The trained ML models have been also applied to own and literature experimental cases, showing a maximum and average error equal to 8.00% and 5.70%, respectively, thus proving once again its reliability.


2011 ◽  
Vol 213 ◽  
pp. 221-225 ◽  
Author(s):  
Jeong Hwan Jang ◽  
Byeong Don Joo ◽  
Sung Min Mun ◽  
Young Hoon Moon

Studies on the forming characteristics by a rotary swaging process using the sub-scale specimens have been carried out to obtain a shell body nose of desirable quality. To analyze the changes of the nose thickness and length at the respective reduction of inside diameter, the finite element simulations were carried out. As a result, the desired target dimension is satisfied with the diameter reduction of more than 64 % for the given preform. The thickness of nose area increased up to 56.1 % from initial thickness of 2.62 mm to 4.09 mm after swaging. The values of the hardness before and after swaging were 208 HV and 325 HV, respectively. To analyze the dimensional changes (length and thickness) of nose area with decreasing inside diameter, the rotary swaging test was carried out for two different diameter reductions such as 65 % and 67 %. The lengths of nose area for the diameter reductions are 11.79 mm in 65 % and 12.53 mm in 67 %, respectively. At the diameter reduction of more than 67%, the crack occurs when the localized strain hardening reduces ductility in internal area. Therefore, the nose area should be formed from 64% to 67% reduction in target inner diameter.


2013 ◽  
Vol 325-326 ◽  
pp. 476-479 ◽  
Author(s):  
Lin Suo Zeng ◽  
Zhe Wu

This article is based on finite element theory and use ANSYS simulation software to establish electric field calculation model of converter transformer for a ±800kV and make electric field calculation and analysis for valve winding. Converter transformer valve winding contour distribution of electric field have completed in the AC, DC and polarity reversal voltage.


2015 ◽  
Vol 809-810 ◽  
pp. 443-448 ◽  
Author(s):  
Tomasz Kik ◽  
Marek Slovacek ◽  
Jaromir Moravec ◽  
Mojmir Vanek

Simulation software based on a finite element method have significantly changed the possibilities of determining welding strains and stresses at early stages of product design and welding technology development. But the numerical simulation of welding processes is one of the more complicated issues in analyses carried out using the Finite Element Method. A welding process thermal cycle directly affects the thermal and mechanical behaviour of a structure during the process. High temperature and subsequent cooling of welded elements generate undesirable strains and stresses in the structure. Knowledge about the material behaviour subjected to the welding thermal cycle is most important to understand process phenomena and proper steering of the process. The study presented involved the SYSWELD software-based analysis of MIG welded butt joints made of 1.0 mm thickness, 5xxx series aluminium alloy sheets. The analysis of strains and the distribution of stresses were carried out for several different cases of fixing and releasing of welded elements.


2013 ◽  
Vol 805-806 ◽  
pp. 552-556
Author(s):  
Ying Xu ◽  
Xiao Yan Liu

In chilliness area, the temperature drop of oil in buried pipeline is affected by soil temperature field, and the thermal diffusivity is one of the main of physical property the soil, which affects the temperature drop of oil directly. This paper introduced the test principle of the thermal diffusivity of soil, and researched the influence of thermal diffusivity of soil on the soil physical property, such as soil natural temperature field, soil frozen days, depth of freezing and temperature delay, which can offer theory support for the calculation of hot oil temperature drop in buried pipeline.


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