scholarly journals Design and Validation of Thermal Insulation for Deep-sea Fluid Sampler of Jiaolong Human Occupied Vehicle

2021 ◽  
Vol 2095 (1) ◽  
pp. 012070
Author(s):  
Kaiben Yu ◽  
Le Zong ◽  
Shengqi Yu ◽  
Qingjian Meng ◽  
Baohua Liu
Keyword(s):  
Experimental Study ◽  
Thermal Insulation ◽  
Deep Sea ◽  
Silica Aerogel ◽  
Simulation Analysis ◽  
Maximum Temperature ◽  
Vehicle Simulation ◽  
Variation Characteristics ◽  
Insulation Effect ◽  
Insulation Performance

Abstract In this paper, a thermal insulation structure with silica aerogel felt as filler material was designed for the requirements of deep-sea fluid thermal insulation sampling technology for Jiaolong human occupied vehicle. Simulation analysis of thermal insulation performance was carried out and an experimental prototype was developed for the thermal insulation structure. Experimental study on thermal insulation performance was conducted with the variation characteristics of the operation environment for Jiaolong human occupied vehicle being taken into account. Results show that the silica aerogel felt with a thickness of 30 mm filled in the radial space between the inner and outer cylinders can achieve the expected thermal insulation effect during the diving-sampling-transferring process, with maximum temperature rise of 8.5 °C, and can meet the requirements of deep-sea fluid thermal insulation sampling technology.

scholarly journals Investigation of the Insulation Effect of Thermal Insulation Layer in the Seasonally Frozen Region Tunnel: A Case Study in the Zuomutai Tunnel, China

2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
Pengyu Zhao ◽  
Jianxun Chen ◽  
Yanbin Luo ◽  
Lijun Chen ◽  
Yao Li ◽  
...  
Keyword(s):  
Thermal Insulation ◽  
Air Temperature ◽  
Ground Surface ◽  
Maximum Temperature ◽  
Insulation Layer ◽  
Tunnel Length ◽  
Maximum Temperature Difference ◽  
Insulation Effect ◽  
Two Sides

In this study, a field temperature test was performed to reveal the insulation effect of the thermal insulation layer installed at lining surface. The thermal insulation layer is made of polyphenolic, and the thickness is 7 cm. According to the test results, the temperature of the thermal insulation layer and lining continuously changes with the air temperature in the tunnel in an approximately trigonometric function. The temperature of tunnel lining without thermal insulation layer is close to the air temperature, which results in the lining frost in winter. The maximum temperature difference between the two sides of the thermal insulation layer can be 27°C. In the section whose buried depth is more than 11.4 m, the temperature of lining with thermal insulation layer in winter is mainly influenced by the cold air in the tunnel. When the monthly mean and lowest daily mean air temperature are lower than −10°C and −14.3°C in the coldest month, the temperature at the inner side of the thermal insulation layer is below 0°C. When the buried depth is less than 11.4 m, the temperature of lining is also influenced by the low temperature at ground surface. The temperature of lining is lower. The thicker thermal insulation layer and even active heat measure are needed. Therefore, the design of thermal insulation layer thickness should consider the air temperature distribution and tunnel buried depth along the tunnel length.

Study on the Thermal Insulation Performance of PAN Pre-Oxidised Fibre Felts

2020 ◽  
Vol 28 (3(141)) ◽  
pp. 27-37
Author(s):  
Xiaoming Zhao ◽  
Yuanjun Liu ◽  
Tenglong Liang
Keyword(s):  
Thermal Conductivity ◽  
Thermal Stability ◽  
Tensile Strength ◽  
Tensile Properties ◽  
Thermal Insulation ◽  
Silica Aerogel ◽  
Orthogonal Experiment ◽  
Excellent Thermal Stability ◽  
Coefficient Of Thermal Conductivity ◽  
Insulation Performance

In this paper, an orthogonal experiment of 3 factors and 3 levels was firstly designed to prepare PAN pre-oxidised fibre felts with good thermal insulation properties; the range method was used to analyse the result of the orthogonal experiment, and finally the tensile properties and thermal stability were tested. Finally, pre-oxidised fibre felt composites for the coating of silica aerogel were prepared using the coating process to compound silica aerogel on re-oxidised fibre felts. Firstly, the influence of the content of silica aerogel on the heat insulation performance of the coated composite materials was analysed, and then a test of the coefficient of thermal conductivity, an experiment on the back temperature, and characterisations of the tensile properties and thermal stability of the composite coating of pre-oxidised fibre felt composites of the coating of silica aerogel were carried out. Results showed that through analysis of the orthogonal experiment, we can state that the best preparation process of pre-oxidised fibre needled felts was as follows: needle number – 2, needle depth – 8 mm, and needle frequency – 140 times/min. The transverse tensile strength of PAN pre-oxidised fibre needled felts prepared by crossly webbing of PAN pre-oxidised fibres was superior to the longitudinal tensile strength; thermogravimetric analysis showed that the pre-oxidised fibre needled felts had excellent thermal stability. The coefficient of thermal conductivity of the aerogel coating of the composites firstly decreased and then increased with an increase in the content of aerogel. Coated composites had the lowest coefficient of thermal conductivity when the aerogel content was 4% wt. At temperatures of 100 °C, 150 °C and 200 °C, the heating rate of the transient-state back temperature and the steady-state average temperature were both the lowest when the aerogel content was 6% wt.

scholarly journals Cost-Effective Additive Manufacturing of Ambient Pressure-dried Silica Aerogel

2020 ◽  
pp. 1-32
Author(s):  
Zipeng Guo ◽  
Ruizhe Yang ◽  
Tianjiao Wang ◽  
Lu An ◽  
Shenqiang Ren ◽  
...  
Keyword(s):  
Thermal Insulation ◽  
Silica Aerogel ◽  
Processing Time ◽  
Ambient Pressure ◽  
Cost Effective ◽  
Supercritical Drying ◽  
Insulation Material ◽  
Market Demand ◽  
Insulation Property ◽  
Insulation Performance

Abstract The conventional manufacturing processes of aerogel insulation material is largely relying on the supercritical drying, which suffers from issues of massive energy consumption, high-cost equipment, and prolonged processing time. With the consideration of large market demand of the aerogel insulation material in the next decade, a low-cost and scalable fabrication technique is highly desired. In this paper, a direct ink writing (DIW) method is used to three-dimensionally fabricate the silica aerogel insulation material, followed by room-temperature and ambient pressure drying. Compared to the supercritical drying and freeze-drying, the reported method significantly reduces the fabrication time and costs. The cost-effective DIW technique offers the capability to print complex hollow internal structures, coupled with the porous structure, is found to be beneficial to the thermal insulation property. The addition of fiber to the ink assures the durability of the fabricated product, without sacrificing the thermal insulation performance. The foam ink preparation methods and the printability are demonstrated in this paper, along with the printing of complex three-dimensional geometries. The thermal insulation performance of the printed objects is characterized, and the mechanical properties are also examined. The proposed approach is found to have 56% reduction in the processing time. The printed silica aerogels exhibit a low thermal conductivity of 0.053 W m−1 K−1.

scholarly journals Microstructure and Thermal Insulation Property of Silica Composite Aerogel

Materials ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 993 ◽  
Author(s):  
Lei Shang ◽  
Yang Lyu ◽  
Wenbo Han
Keyword(s):  
Thermal Insulation ◽  
Silica Aerogel ◽  
Infrared Radiation ◽  
Performance Test ◽  
Heat Insulation ◽  
Insulation Material ◽  
Cold Surface ◽  
Composite Aerogel ◽  
Aerogel Composite ◽  
Insulation Performance

Tetraethyl orthosilicate was selected as a matrix of heat insulating materials among three silanes, and an anti-infrared radiation fiber was chosen as a reinforcement for silica aerogel insulation composite. The silica aerogel was combined well and evenly distributed in the anti-infrared radiation fiber. The heat insulation effect was improved with the increase in thickness of the aerogel insulation material, as determined by the self-made aerospace insulation material insulation performance test equipment. The 15 mm and 30 mm thick thermal insulation material heated at 250 °C for 3 h, the temperatures at the cold surface were about 80 °C and 60 °C, respectively, and the temperatures at 150 mm above the cold surface were less than 60 °C and 50 °C, respectively. The silica aerogel composites with various thicknesses showed good thermal insulation stability. The silica insulation composite with a thickness of 15 mm exhibited good heat insulation performance, meets the thermal insulation requirements of general equipment compartments under low-temperature and long-term environmental conditions. The thermal conductivity of prepared silica aerogel composite was 0.0191 W·m−1·k−1 at room temperature and 0.0489 W·m−1·k−1 at 500 °C.

The Insulated Effect of New Inorganic Coatings on the Surface of Fiber Paper

2008 ◽  
Vol 373-374 ◽  
pp. 682-685
Author(s):  
Fei He ◽  
Xiao Dong He ◽  
J.F. Li ◽  
Ming Wei Li ◽  
S.M. Zhang
Keyword(s):  
High Temperature ◽  
Thermal Insulation ◽  
Random Network ◽  
Inorganic Coatings ◽  
Insulation Effect ◽  
Service Conditions ◽  
Fiber Materials ◽  
Insulation Performance ◽  
Continuous Random Network ◽  
Made In

The unitary thermal insulation fiber materials can not satisfy rigorous high temperature environment usually. New inorganic coatings were prepared by adding SiO2 aerogels super-insulation powder into high temperature adhesive. Aerogels are high dispersive solid materials which consist of colloid particles or high polymer molecule and have continuous random network structure filling with gaseous dispersive medium. The coatings with super insulation function were made by means of adding thermal-proof materials to the coatings. The microstructure of light porous power and the states of coatings on the surface of fiber paper under different state were observed by scanning electron microscope (SEM). The insulated effect of the composite materials was tested by considering thermal conductivity. On the basis of this, the coatings on the surface of fiber paper were optimized according to the material thermal-insulation performance and the materials that could be satisfactory to the service conditions were made in the end. The results show that silica aerogels powder is dispersed equably in high temperature adhesive. The new inorganic coatings possess themselves of good thermal-insulation effect and can be used as insulated space-layers. The insulation ability of fiber paper is improved obviously.

scholarly journals Thermal Insulation Performance of Radiant Barrier Roofs for Rural Buildings in the Qinba Mountains

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Yiyun Zhu ◽  
Xianling Wang
Keyword(s):  
Thermal Insulation ◽  
Simulation Analysis ◽  
Thermal Environment ◽  
Aluminum Foil ◽  
Radiant Heat ◽  
Climatic Conditions ◽  
Radiant Heat Transfer ◽  
Barrier Materials ◽  
Rural Buildings ◽  
Insulation Performance

Strengthening the roof insulation is the main method for improving the indoor thermal environment of rural buildings during summer. This study proposed a radiant barrier roof with a roof insulation structure based on climatic conditions in the Qinba Mountains and the characteristics of rural buildings, in which radiant barriers were installed on the underside of the roof in the attic space to enhance roof insulation. To study the thermal insulation performance of radiant barrier roofs, aluminum foil bubble composites were installed on the underside of the roof in the attic space in the Qinba Mountains, and comparative experiments were carried out. Based on the results, the average temperature of the second-floor bedrooms dropped by 1.1°C, thus proving the effectiveness of thermal insulation with radiant barrier roofs. The thermal insulation performance of radiant barrier roofs made of aluminum foil bubble composite was studied through numerical simulation analysis. Based on the findings of this study, radiant heat transfer contributed 65% to the thermal insulation effect when aluminum foil bubble composites were applied. Based on the analysis of thermal performance and cost, it is recommended to use radiant barrier materials with an emissivity of less than 0.3 and a thermal resistance of no more than 2 m2K/W. Furthermore, the application of radiant barrier roofs made of aluminum foil bubble composites can have a positive effect on thermal insulation during winter. This facilitates the widespread use of radiant barrier roofs for rural buildings throughout hot-summer/cold-winter zones.

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