共查询到16条相似文献,搜索用时 78 毫秒
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内锥流量计与孔板流量计的压力损失及能耗研究 总被引:1,自引:1,他引:0
通过CFD流体软件对内锥流量计压力损失进行了数值模拟,实验介质为汽油与柴油的混合物。内锥流量计和孔板流量计经常使用于流体计量,在保证两种流量计流通面积相等的条件下,对它们的压力损失进行了比较。结果表明,内锥流量计的压力损失仅为孔板流量计压力损失的30%左右,将内锥流量计应用于流体计量,可以起到节能降耗的作用。 相似文献
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在传统汽车发动机的基础上设计了P2双离合结构48 V轻混动力系统,以提高燃油经济性和降低排放为目的,制定了以SOC、需求转矩、车速以及制动强度为输入,电机转矩分配系数、再生制动比例系数为输出的双模糊控制策略.在AVL-CRUISE中搭建了48 V轻混动力汽车模型,与MATLAB联合,在NEDC工况下进行仿真,与传统汽车... 相似文献
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基于两相界面追踪方法 VOF(volume of fluid)研究生物油在离心式喷嘴内的雾化特性,考察喷射流量对流量系数、雾化锥角和液膜厚度的影响,并与生物油/甲醇混合燃料的雾化特性进行对比。结果表明:喷射流量对雾化锥角及液膜厚度有较大影响,对流量系数影响较小。喷射流量从0.03 kg/s增至0.12 kg/s,流量系数增大3.4%,雾化锥角增大30.6%,而液膜厚度减小22.3%;雾化锥角随甲醇含量的增大呈线性递增,而液膜厚度随甲醇含量的增大呈线性递减;利用数值结果拟合得到生物油液膜厚度的经验公式,拟合值和数值计算值吻合较好。 相似文献
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为加深对多孔介质发动机中均匀混合气形成的了解,用改进的KIVA-3V详细模拟了空心喷雾油滴碰撞热多孔介质的过程。在KIVA-3V中增加了油滴碰撞热多孔介质壁面的碰撞模型、传热模型及空心喷雾的线性不稳定性液膜破碎(LISA)模型。油滴与热壁的碰撞模型和传热模型经检验证明了其合理性。在简化多孔介质结构的基础上,在不同的环境压力及喷雾锥角下,模拟了空心喷雾与热多孔介质的相互作用。计算结果表明:油雾在碰撞到热多孔介质后,发生分裂的油束和多孔介质区域的高温,促使油滴实现快速蒸发并为油蒸汽与空气充分混合创造了前提。不同的空间压力及喷雾锥角直接影响到油滴在多孔介质中的分布。 相似文献
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S. Shaaban 《International Journal of Hydrogen Energy》2017,42(21):14621-14632
The wide spreading hydrogen energy requires accurate flow measurement. Constriction type flowmeters could be a favorable candidate for liquid hydrogen. However, their permanent pressure losses and installation length could significantly increase the manufacturing, installation, metering, maintenance, and replacement cost. The high permanent pressure losses may also cause cavitation. The present research introduces a novel constriction type flowmeter with an optimized flow profile. Numerical simulation, as well as multidimensional and multi-objective optimization, was utilized in order to minimize the flowmeter's loss coefficient and the required installation length. The applied optimization technique results in significant improvements of the flowmeter design and performance. The proposed flowmeter is shorter than the standard Venturi nozzle by 67.2% and its loss coefficient is lower by up to 10.6%. It measures the flow rate of liquid hydrogen with up to 25.5% higher discharge coefficient and 83.7% lower loss coefficient compared to a corresponding perforated plate flowmeter. Cavitation was not detected inside the proposed flowmeter up to a Reynolds number of 2.2 × 106. The present investigation shows that the proposed flowmeter is very promising for liquid hydrogen measurement. 相似文献
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PIECHOTA Piotr SYNOWIEC Piotr ANDRUSZKIEWICZ Artur W?DRYCHOWICZ Wies?aw 《热科学学报(英文版)》2018,27(5):413-420
The article is an attempt to compile the results of CFD liquid flow simulation through pipeline section containing hydraulic elbow with the results of ultrasonic flow measurements. To carry out the measurements behind the flow disturbing element (hydraulic elbow), an ultrasonic flowmeter with applied head set in accordance with the Z-type system was used. For comparative purposes, a flow simulation for 3 different turbulence models (k-epsilon, SST and SSG) was performed. It was found that with a proper ultrasonic flowmeter heads configurations, it is possible to measure the flow rate disturbed by the hydraulic elbow at any distance from the source of the disturbance. It has to use appropriate correction factor that can be determined by knowing the flow velocity profile equation. Based on comparison of CFD simulation results with experimental data, the accuracy/ purposefulness of using individual turbulence models in the case of discussed hydraulic installation was evaluated. 相似文献
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针对热电厂供汽管道压力损失偏大的原因,对阻力大并影响供汽能力的喷水减温器、直管旁通外压式压力平衡膨胀节进行改造,用旋转膨胀节代替横向波纹膨胀节、弯管流量计取代孔板流量计,降低3条供汽管道压力损失0.12~0.24MPa,增大了新蒸汽的可利用焓降。在维持用户参数不变的情况下,3台供热机组每年可多发电14536.30MW,增加热电厂利润476.73万元,节能效益显著。 相似文献