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叶栅稠度对多翼离心风机性能影响的研究 被引量:1
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作者 凌敬 刘乾坤 +1 位作者 季振勤 冀春俊 《风机技术》 2017年第3期29-33,共5页
用数值模拟方法对风机的性能参数和三维流场结构变化进行分析,研究叶栅稠度对小型多翼离心风机性能的影响。数值模拟结果表明:多翼离心风机的流量、全压、全压效率都随叶栅稠度增大先增大后减小,存在最佳稠度使风机的性能最优;叶栅稠度... 用数值模拟方法对风机的性能参数和三维流场结构变化进行分析,研究叶栅稠度对小型多翼离心风机性能的影响。数值模拟结果表明:多翼离心风机的流量、全压、全压效率都随叶栅稠度增大先增大后减小,存在最佳稠度使风机的性能最优;叶栅稠度小时,叶片的负荷大,叶轮容易产生大尺度流动分离,尤其是在径向速度较小的叶顶附近,严重时可能造成风机失速,流动损失增大,风机性能下降;叶栅稠度大时,叶片表面积大,附面层摩擦损失大,风机效率低,同时叶片数多使叶轮通流面积减小,流动阻塞,风机流量降低。 展开更多
关键词 多翼离心风机 稠度 流量 全压 效率
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Design of a low power GPS receiver in 0.18 μm CMOS technology with a ΣΔ fractional-N synthesizer 被引量:1
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作者 Di LI Yin-tang YANG +7 位作者 Jiang-an WANG Bing LI Qiang LONG Jary WEI Nai-di WANG Lei WANG qian-kun liu Da-long ZHANG 《Journal of Zhejiang University-Science C(Computers and Electronics)》 SCIE EI 2010年第6期444-449,共6页
A 19 mW highly integrated GPS receiver with a ΣΔ fractional-N synthesizer is presented in this paper.Fractional-N frequency synthesizer architecture was adopted in this work, to provide more degrees of freedom in th... A 19 mW highly integrated GPS receiver with a ΣΔ fractional-N synthesizer is presented in this paper.Fractional-N frequency synthesizer architecture was adopted in this work, to provide more degrees of freedom in the synthesizer design.A high linearity low noise amplifier(LNA) is integrated into the chip.The radio receiver chip was fabricated in a 0.18 μm complementary metal oxide semiconductor(CMOS) process and packaged in a 48-pin 2 mm×2 mm land grid array chip scale package.The chip consumes 19 mW(LNA1 excluded) and the LNA1 6.3 mW.Measured performances are:noise figure<2 dB, channel gain=108 dB(LNA1 included), image rejection>36 dB, and-108 dBc/Hz @ 1 MHz phase noise offset from the carrier.The carrier noise ratio(C/N) can reach 41 dB at an input power of-130 dBm.The chip operates over a temperature range of-40, 120 °C and ±5% tolerance over the CMOS technology process. 展开更多
关键词 GPS receiver ΣΔ fractional-N synthesizer Image rejection Phase noise
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