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主动防堵 1

保护性耕作 1

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Improvement of solidification model and analysis of 3D channel blockage with MPS method

《能源前沿（英文）》 2021年第15卷第4期页码 946-958 doi: 10.1007/s11708-021-0754-z

摘要： In a severe accident of a nuclear power reactor, coolant channel blockage by solidified molten core debris may significantly influence the core degradations that follow. The moving particle semi-implicit (MPS) method is one of the Lagrangian-based particle methods for analyzing incompressible flows. In the study described in this paper, a novel solidification model for analyzing melt flowing channel blockage with the MPS method has been developed, which is suitable to attain a sufficient numerical accuracy with a reasonable calculation cost. The prompt velocity diffusion by viscosity is prioritized over the prompt velocity correction by the pressure term (for assuring incompressibility) within each time step over the “mushy zone” (between the solidus and liquidus temperature) for accurate modeling of solidification before fixing the coordinates of the completely solidified particles. To sustain the numerical accuracy and stability, the corrective matrix and particle shifting techniques have been applied to correct the discretization errors from irregular particle arrangements and to recover the regular particle arrangements, respectively. To validate the newly developed algorithm, 2-D benchmark analyses are conducted for steady-state freezing of the water in a laminar flow between two parallel plates. Furthermore, 3-D channel blockage analyses of a boiling water reactor (BWR) fuel support piece have been performed. The results show that a partial channel blockage develops from the vicinity of the speed limiter, which does not fully develop into a complete channel blockage, but still diverts the incoming melt flow that follows to the orifice region.

关键词： boiling water reactor (BWR) severe accident channel blockage moving particle semi-implicit (MPS) method solidification

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轻型高防堵性能免耕播种机研究

高焕文,李洪文,姚宗路

《中国工程科学》 2007年第9卷第9期页码 35-39

摘要：

以主动防堵的思路，提高国产免播机质量与尺寸受限情况下的防堵性能。先后研制出带状旋耕、条带粉碎和驱动圆盘3种主动防堵的轻型免播机，防堵能力强，能胜任高产玉米地免耕播种小麦，质量316~500 kg/m，与国产拖拉机匹配，价格为国外免播机1/8左右。田间对比试验表明，轻型主动防堵免播机动土量和动力消耗比国外免播机大一些，但在小麦出苗、长势和产量上优于国外机器。2006年推广近 2万台，玉米地免耕播种小麦约 40×104 hm2。

关键词：主动防堵免耕播种机轻型机具保护性耕作直接播种小麦

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Lagrangian simulation of deposition of CO gas-solid sudden expansion flow

HUANG Dongping, DING Guoliang, QUACK Hans

《能源前沿（英文）》 2008年第2卷第2期页码 216-221 doi: 10.1007/s11708-008-0032-3

摘要： Freezing and blockage resulting from the deposition of solid CO formed because of sudden expansion of the downstream pipe during the release of CO through safety valves, will endanger the protected equipment. To overcome this problem, the characteristics of the CO gas-solid sudden expansion flow are studied by using the disperse Lagrangian model. A comparison of the calculated deposition of the solid CO with the experimental results shows that they are in reasonable agreement. The simulation results show that the size of the solid CO formed should not be in the range of 0.04–0.07 mm ( number 3.2–9.8). This can be achieved by using an appropriate flow cross section of the safety valve.

关键词： comparison gas-solid downstream blockage Lagrangian

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Aerodynamic performance of bowed compressor cascades with different camber angles

CHEN Shaowen, CHEN Fu, WANG Keli, GU Jun, WANG Zhongqi

《能源前沿（英文）》 2008年第2卷第3期页码 306-312 doi: 10.1007/s11708-008-0056-8

摘要： The effects of a positively bowed blade on the aerodynamic performance of annular compressor cascades with different camber angles were experimentally investigated. The distributions of the exit total pressure loss and secondary flow vectors of the compressor cascades were analyzed. The static pressure was measured by tapping on the cascade surfaces, and the ink-trace flow visualizations were conducted. The results show that the value of the optimum bowed angle and optimum bowed height decrease because of the increased losses at the mid-span with the increase of the camber angle. The C-shape static pressure distribution along the radial direction exists on the suction surface of the straight cascade with larger camber angles. When bowed blade is applied, the larger bowed angle and larger bowed height will further enhance the accumulation of the low-energy fluid at the mid-span, thus causing the flow behavior to deteriorate. Under 60° camber angle, flow behavior near the end-wall region of some bowed cascades even deteriorates instead of improving because the blockage of the separated flow near the mid-span keeps the low-energy fluid near the end-walls from moving towards the mid-span region. As a result, a rapid augmentation of the total loss can easily take place under a large bowed angle.

关键词： increase different blockage increased ink-trace

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Blockage of receptor-interacting protein 2 expression by small interfering RNA in murine macrophages

LIU Hongchun, CAO Zhongwei, JIN Jianjun, WANG Jiyao

《医学前沿（英文）》 2008年第2卷第2期页码 166-170 doi: 10.1007/s11684-008-0030-1

摘要： This study aims to demonstrate that blocking the receptor-interacting protein2 (Rip2) expression can decrease inflammatory cytokine production by macrophage and protect mice from endotoxin lethality. Murine Rip2 small interfering RNA (siRNA) plasmids were constructed and transfected into macrophage and Rip2 expression was detected with reverse transcription-polymerase chain reaction (RT-PCR) and western blot. Cell proliferation was assayed with MTT. TNF-? concentration was assayed with ELISA and high-mobility group box 1 protein (HMGB1) level with semi-quantitative western blot after lipopolysaccharide (LPS) stimulation. LPS challenge was given after the plasmids were injected into mice and the survival rate was calculated. Rip2 siRNA plasmid could block the mRNA and protein expression of Rip2 and promote cell proliferation. Blocking Rip2 could attenuate LPS-induced TNF-? and HMGB1 production. The HMGB1 expression in the liver decreased to (40.21 ± 11.03) pg/g, and serum TNF-? level decreased to (300.43 ± 59.26) ng/L ( < 0.05). The survival rate of mice from endotoxemia was also improved ( < 0.05). The results demonstrate that Rip2 siRNA plasmid can block the expression of Rip2, decrease the production of TNF-? and HMGB1 and protect mice from fatal endotoxemia.

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Mechanism and control factors of hydrate plugging in multiphase liquid-rich pipeline flow systems: a review

Shuwei ZHANG, Liyan SHANG, Zhen PAN, Li ZHOU, You GUO

《能源前沿（英文）》 2022年第16卷第5期页码 747-773 doi: 10.1007/s11708-022-0830-z

摘要： There is nothing illogical in the concept that hydrates are easily formed in oil and gas pipelines owing to the low-temperature and high-pressure environment, although requiring the cooperation of flow rate, water content, gas-liquid ratio, and other specific factors. Therefore, hydrate plugging is a major concern for the hydrate slurry pipeline transportation technology. In order to further examine potential mechanisms underlying these processes, the present paper listed and analyzed the significant research efforts specializing in the mechanisms of hydrate blockages in the liquid-rich system, including oil-based, water-based, and partially dispersed systems (PD systems), in gathering and transportation pipelines. In addition, it summarized the influences of fluid flow and water content on the risk of hydrate blockage and discussed. In general, flow rate was implicated in the regulation of blockage risk through its characteristic to affect sedimentation tendencies and flow patterns. Increasing water content can potentiate the growth of hydrates and change the oil-water dispersion degree, which causes a transition from completely dispersed systems to PD systems with a higher risk of clogging. Reasons of diversity of hydrate plugging mechanism in oil-based system ought to be studied in-depth by combining the discrepancy of water content and the microscopic characteristics of hydrate particles. At present, it is increasingly necessary to expand the application of the hydrate blockage formation prediction model in order to ensure that hydrate slurry mixed transportation technology can be more maturely applied to the natural gas industry transportation field.

关键词： hydrate flow rate water content mechanism of pipeline blockage rich liquid phase system