Numerical Simulations on the Low-Pressure Water-Injection-Induced Seepage Rules of Coal with Pre-existing Plane/Surface Fractures

2019 ◽  
Vol 37 (4) ◽  
pp. 3283-3297 ◽  
Author(s):  
Gang Zhou ◽  
Wen-jing Yin ◽  
Xing Wei
Fuel ◽  
2022 ◽  
Vol 307 ◽  
pp. 121795
Author(s):  
Jian Chen ◽  
Weimin Cheng ◽  
Gang Wang ◽  
Haomiao Li

2021 ◽  
Author(s):  
Eva Alvarez-Regueiro ◽  
Esperanza Barrera-Medrano ◽  
Ricardo Martinez-Botas ◽  
Srithar Rajoo

Abstract This paper presents a CFD-based numerical analysis on the potential benefits of non-radial blading turbine for low speed-low pressure applications. Electric turbocompounding is a waste heat recovery technology consisting of a turbine coupled to a generator that transforms the energy left over in the engine exhaust gases, which is typically found at low pressure, into electricity. Turbines designed to operate at low specific speed are ideal for these applications since the peak efficiency occurs at lower pressure ratios than conventional high speed turbines. The baseline design consisted of a vaneless radial fibre turbine, operating at 1.2 pressure ratio and 28,000rpm. Experimental low temperature tests were carried out with the baseline radial blading turbine at nominal, lower and higher pressure ratio operating conditions to validate numerical simulations. The baseline turbine incidence angle effect was studied and positive inlet blade angle impact was assessed in the current paper. Four different turbine rotor designs of 20, 30, 40 and 50° of positive inlet blade angle are presented, with the aim to reduce the losses associated to positive incidence, specially at midspan. The volute domain was included in all CFD calculations to take into account the volute-rotor interactions. The results obtained from numerical simulations of the modified designs were compared with those from the baseline turbine rotor at design and off-design conditions. Total-to-static efficiency improved in all the non-radial blading designs at all operating points considered, by maximum of 1.5% at design conditions and 5% at off-design conditions, particularly at low pressure ratio. As non-radial fibre blading may be susceptible to high centrifugal and thermal stresses, a structural analysis was performed to assess the feasibility of each design. Most of non-radial blading designs showed acceptable levels of stress and deformation.


2002 ◽  
Vol 2002 (5-1) ◽  
pp. 161-166
Author(s):  
Yoshihiro Yata ◽  
Takeshi Nakada ◽  
Yasuo Sakurai ◽  
Kazuhiro Tanaka

2018 ◽  
Vol 4 (3) ◽  
Author(s):  
Kenji Iino ◽  
Ritsuo Yoshioka ◽  
Masao Fuchigami ◽  
Masayuki Nakao

Abstract The Great East Japan Earthquake on Mar. 11, 2011 triggered huge tsunami waves that attacked Fukushima Daiichi Nuclear Power Plant (Fukushima-1). Units 1, 3, and 4 had hydrogen explosions. Units 1–3 had core meltdowns and released a large amount of radioactive material. Published investigation reports did not explain how the severity of the accident could have been prevented. We formed a study group to find: (A) Was the earthquake-induced huge tsunami predictable at Fukushima-1? (B) If it was predictable, what preparations at Fukushima-1 could have avoided the severity of the accident? Our conclusions were: (a) The tsunami that hit Fukushima-1 was predictable, and (b) the severity could have been avoided if the plant had prepared a set of equipment, and most of all, had exercised actions to take against such tsunami. Necessary preparation included: (1) a number of direct current (DC) batteries, (2) portable underwater pumps, (3) portable alternating current (AC) generators with sufficient gasoline supply, (4) high voltage AC power trucks, and (5) drills against extended loss of all electric power and seawater pumps. This set applied only to this specific accident. A thorough preparation would have added (6) portable compressors, (7) watertight modification to reactor core isolation cooling system (RCIC) and high pressure coolant injection system (HPCI) control and instrumentation, and (8) fire engines for alternate low pressure water injection. Item (5), i.e., to study plans and carry out exercises against the tsunami would have identified all other necessary preparations.


Applied laser ◽  
2013 ◽  
Vol 33 (2) ◽  
pp. 181-185
Author(s):  
王金华 Wang Jinhua ◽  
袁根福 Yuan Genfu ◽  
逄志伟 Pang Zhiwei ◽  
陈春映 Chen Chunying

Applied laser ◽  
2014 ◽  
Vol 34 (4) ◽  
pp. 323-326
Author(s):  
陆平卫 Lu Pingwei ◽  
袁根福 Yuan Genfu

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