scholarly journals Pore-scale analysis of coal structure and mechanical properties evolution through liquid nitrogen thermal shock

Author(s):  
Ruiyue Yang ◽  
Richao Cong ◽  
Han Liu ◽  
Zhongwei Huang ◽  
Haitao Wen ◽  
...  
2020 ◽  
Vol 219 ◽  
pp. 103370 ◽  
Author(s):  
Hamed Akhondzadeh ◽  
Alireza Keshavarz ◽  
Ahmed Z. Al-Yaseri ◽  
Muhammad Ali ◽  
Faisal Ur Rahman Awan ◽  
...  

2021 ◽  
pp. 1-18
Author(s):  
Mansoureh Khaljani ◽  
Meysam Nazari ◽  
Mahdi Azarpeyvand ◽  
Yasser Mahmoudi

2018 ◽  
Vol 44 (2) ◽  
pp. 1589-1593 ◽  
Author(s):  
Dongdong Qian ◽  
Lei Zhang ◽  
Ying Zhang ◽  
Pingying Liu ◽  
Xizhang Wang ◽  
...  

2017 ◽  
Vol 31 (12) ◽  
pp. 13221-13232 ◽  
Author(s):  
Mehdi Shabaninejad ◽  
Jill Middleton ◽  
Shane Latham ◽  
Andrew Fogden

2018 ◽  
Vol 36 (6) ◽  
pp. 1609-1628 ◽  
Author(s):  
Chengzheng Cai ◽  
Feng Gao ◽  
Yugui Yang

Liquid nitrogen is a type of super-cryogenic fluid, which can cause the reservoir temperature to decrease significantly and thereby induce formation rock damage and cracking when it is injected into the wellbore as fracturing fluid. An experimental set-up was designed to monitor the acoustic emission signals of coal during its contact with cryogenic liquid nitrogen. Ultrasonic and tensile strength tests were then performed to investigate the effect of liquid nitrogen cooling on coal cracking and the changes in mechanical properties thereof. The results showed that acoustic emission phenomena occurred immediately as the coal sample came into contact with liquid nitrogen. This indicated that evident damage and cracking were induced by liquid nitrogen cooling. During liquid nitrogen injection, the ring-down count rate was high, and the cumulative ring-down counts also increased rapidly. Both the ring-down count rate and the cumulative ring-down counts during liquid nitrogen injection were much greater than those in the post-injection period. Liquid nitrogen cooling caused the micro-fissures inside the coal to expand, leading to a decrease in wave velocity and the deterioration in mechanical strength. The wave velocity, which was measured as soon as the sample was removed from the liquid nitrogen (i.e. the wave velocity was recorded in the cooling state), decreased by 14.46% on average. As the cryogenic samples recovered to room temperature, this value increased to 18.69%. In tensile strength tests, the tensile strengths of samples in cooling and cool-treated states were (on average) 17.39 and 31.43% less than those in initial state. These indicated that both during the cooling and heating processes, damage and cracking were generated within these coal samples, resulting in the acoustic emission phenomenon as well as the decrease in wave velocity and tensile strength.


2012 ◽  
Vol 455-456 ◽  
pp. 650-654 ◽  
Author(s):  
He Yi Ge ◽  
Jian Ye Liu ◽  
Xian Qin Hou ◽  
Dong Zhi Wang

The physical and mechanical properties of nanometer ZrO2-ZrO2fiber composite ceramics were studied by introduction of ZrO2fiber. ZrO2composite ceramics at different sintering temperature was investigated by porosity and water absorption measurements, flexual strength and thermal shock resistance analysis. Results showed that ZrO2composite ceramics containing 15 wt% ZrO2fiber with sintering temperature of 1650°C exhibited good mechanical properties and thermal shock resistance. The porosity and the water absorption were 8.84% and 1.62%, respectively. The flexual strength was 975 MPa and the thermal shock times reached 31 times. Scanning electron microscope (SEM) was used to analyze the microstructure of ZrO2composite ceramics.


Geothermics ◽  
2021 ◽  
Vol 97 ◽  
pp. 102252
Author(s):  
Ning Pai ◽  
Ju Feng ◽  
Su Haijian ◽  
He Zequan ◽  
Xiao Meng ◽  
...  

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