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新型高精度超声波流量计的设计 被引量:6
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作者 宁晨 顾宇 +1 位作者 周康源 陈昕 《声学技术》 CSCD 2003年第4期251-254,261,共5页
文章报导了一种新型高精度超声波流量计的系统设计。利用传统流量计的原理,结合目前先进的可偏程逻辑器件(CPLD)设计和高频电路设计技术,针对高精度、宽量程的要求,设计出具有数字自动增益控制(AGC)系统、自动纠错系统、高频计数系统的... 文章报导了一种新型高精度超声波流量计的系统设计。利用传统流量计的原理,结合目前先进的可偏程逻辑器件(CPLD)设计和高频电路设计技术,针对高精度、宽量程的要求,设计出具有数字自动增益控制(AGC)系统、自动纠错系统、高频计数系统的新型超声波流量计,它具有主从处理器并行工作结构和多种输出方式,可为多种工业输出标准提供接口。文章给出了该系统在实验室和工业环境中测试的结果。 展开更多
关键词 超声波流量计 可偏程逻辑器件 高频电路设计 自动增益控制 自动纠错控制 高频计数 逆流发射 雷诺数
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Influence of angle of attack on a combined opposing jet and platelet transpiration cooling blunt nose in hypersonic vehicle 被引量:3
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作者 Bin-xian SHEN Hong-peng LIU Wei-qiang LIU 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2020年第9期761-769,共9页
Flying condition with angle of attack is inevitable in a hypersonic vehicle,and it may influence the thermal protection system(TPS)performance of opposing jet and its combinations.A 3D Navier–Stokes equation and shea... Flying condition with angle of attack is inevitable in a hypersonic vehicle,and it may influence the thermal protection system(TPS)performance of opposing jet and its combinations.A 3D Navier–Stokes equation and shear stress transfer(SST)k-ωmodel with compressible correction are employed to simulate the angle of attack characteristics of a blunt body with opposing jet and platelet transpiration TPS.The flowfield and heat flux transfer for angles of attack 0°,3°,6°with jet pressure ratio PR=0.1 and 0°,6°,12°with PR=0.2 are obtained.Numerical results show that the flowfield is no longer symmetrical with the effect of the angle of attack.The flowfield and heat transfer in windward and leeward performed adversely.The recompression shock wave in windward is strengthened,which increases local temperature and strengthens heat transfer.The opposing jet fails in thermal protection when the angle of attack reaches critical value;however,the critical angle of attack can be promoted by increasing PR.Finally,the transpiration gas can strengthen the cooling efficiency of windward,thereby,increasing the critical angle of attack. 展开更多
关键词 Thermal protection Opposing jet Platelet transpiration Angle of attack
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