张宁
,
杨敏官
,
高波
,
李忠
,
陆胜
工程热物理学报
基于CFD方法,采用混合两相模型、标准κ-ε方程和sighal发展的全空化模型,对具有特殊结构形式的侧壁式压水室离心泵空化特征进行数值计算.预测了泵在未发生空化和空化条件下的能量性能,并且分析了设计流量下叶片表面和流道内的空泡分布情况.结果表明:在大流量工况下,泵的必需汽蚀余量大,容易产生空化现象.随着泵进口压力的降低,空泡最先出现在泵叶片背面靠近进口边附近;当进口压力进一步降低时,空泡区域开始快速增加,向叶片出口延伸,泵的扬程开始大幅下降.进口压力继续降低时,叶片工作面开始出现空泡,叶轮周向流道内开始充满空泡,此时泵的扬程急剧下降,泵的稳定运行工况被破坏.不同汽蚀余量下,叶频处压力幅值变化明显,在临界汽蚀点处几乎达到极小值.
关键词:
离心泵
,
侧壁式压水室
,
数值计算
,
空化
周婷婷
,
袁成清
,
曹攀
,
王雪君
,
董从林
中国腐蚀与防护学报
doi:10.11902/1005.4537.2013.222
根据流体流动的基本规律,建立了冲刷腐蚀和空化流相变的数学模型,利用Fluent软件对喷油嘴内部流体进行数值模拟分析.结果表明:冲刷腐蚀引起材料损坏的严重位置为喷孔入口拐角处.然而当出现“超空穴”现象时,流体最大剪切应力位置会移至喷孔出口处附近;当腐蚀介质一定时,冲刷腐蚀程度随着燃油粘度、流体流速、进口压力、入口圆角的增大而增大,随着背压增大而减小;在进口压力和流速一定的情况下,降低燃油粘度和背压,减小入口圆角既能减缓流体冲刷腐蚀作用又有利于燃油雾化.
关键词:
喷油嘴
,
冲刷腐蚀
,
空穴
,
剪切应力
,
数值模拟
FENG Di
,
YE Wujun
,
HAN Guangwei
,
LUO Heli(Central Iron Steel Research Institute
,
Beijing 10008 1
,
China)
金属学报(英文版)
Research work and recent progress made toward the industrial applications of the Ni_3Al in CISRI are discussed in present paper. The development of a Ni_3Al base alloy named MX-246 hardened by carbides and fine dispersion of disordered γ is summaried. This alloy,with higher peak temperature of yield strength and higher strain hardening rate than alloyIC-218,has been successfully used as the material of rolling guider at elevated temperatures and in wear conditions. The Ni3Al base alloy of GH264 has been made into welding electrodes by horizontal continuous casting process, and recently successfully surfacing welded on hydraulic blades as cavitation erosion resistance material. The process of remelting Ni3Al base alloy in air was also developed. The processes of producing welding electrodes and remelting in air set the base of industrial applications of Ni3Al in welding, repairing and casting in mass production and into components of large size. Another application of the compound, manufacturing the jet engine rivets used at about 1300℃ , can be attributed to its excellent oxidation resistance and still keeping high strength up to the melting point.
关键词:
: Ni_3Al
,
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,
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,
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