为研究外界因素对风机叶片电阻加热除冰时间的影响规律,以及电阻丝布置方式对融冰过程的影响,该文在多功能人工气候室内对风机叶片进行了电阻加热除冰试验研究,分析了覆冰厚度、环境温度、相对风速和液态水含量(liquid water content,L...为研究外界因素对风机叶片电阻加热除冰时间的影响规律,以及电阻丝布置方式对融冰过程的影响,该文在多功能人工气候室内对风机叶片进行了电阻加热除冰试验研究,分析了覆冰厚度、环境温度、相对风速和液态水含量(liquid water content,LWC)对除冰时间的影响规律,并提出了合理的电阻丝布置方式。结果表明:覆冰厚度较小时,其对除冰时间的影响较为明显,随着覆冰厚度的继续增大,除冰时间无明显差异;除冰时间随加热功率和环境温度的增大而降低,随相对风速和LWC的增大而增大,且不同覆冰厚度下除冰时间随上述因素的变化曲线会有较大不同;叶片尖部电阻丝宜采用弦向布置,根部电阻丝宜采用展向布置;除冰过程中,叶片尖部冰层易发生脱落,根部冰层易被融化。展开更多
The influence of high-density pulsing current on the work-hardening behaviour of H0Cr17Ni6Mn3 and 1Cr18Ni9 stainless steels in wire-drawing deformation processes has been studied. It was found that the drawing stress ...The influence of high-density pulsing current on the work-hardening behaviour of H0Cr17Ni6Mn3 and 1Cr18Ni9 stainless steels in wire-drawing deformation processes has been studied. It was found that the drawing stress and the work-hardening rate of wires were significantly reduced by applying current pulses in drawing process. The work-hardening behavior of the multi-courses drawing deformation can be well described by Hollomon formula σ=κΕn. With the application of current pulses in drawing deformation, the work-hardening exponents of H0Cr17Ni6Mn3 steel wires and 1Cr18Ni9 stainless steel wires were reduced by 33% and 45%, respectively, and their work-hardening coefficients were reduced by 41% and 47%, respectively. It was also found that the work-hardening coefficient of wires was reduced with the increment of the frequency of current pulses, while the work-hardening exponents of both steels were insensitive to the pulsing frequency.展开更多
文摘为研究外界因素对风机叶片电阻加热除冰时间的影响规律,以及电阻丝布置方式对融冰过程的影响,该文在多功能人工气候室内对风机叶片进行了电阻加热除冰试验研究,分析了覆冰厚度、环境温度、相对风速和液态水含量(liquid water content,LWC)对除冰时间的影响规律,并提出了合理的电阻丝布置方式。结果表明:覆冰厚度较小时,其对除冰时间的影响较为明显,随着覆冰厚度的继续增大,除冰时间无明显差异;除冰时间随加热功率和环境温度的增大而降低,随相对风速和LWC的增大而增大,且不同覆冰厚度下除冰时间随上述因素的变化曲线会有较大不同;叶片尖部电阻丝宜采用弦向布置,根部电阻丝宜采用展向布置;除冰过程中,叶片尖部冰层易发生脱落,根部冰层易被融化。
基金supported by the laboratory foundation of Tsinghua Universitythe'985'research foundation of Tsinghua University
文摘The influence of high-density pulsing current on the work-hardening behaviour of H0Cr17Ni6Mn3 and 1Cr18Ni9 stainless steels in wire-drawing deformation processes has been studied. It was found that the drawing stress and the work-hardening rate of wires were significantly reduced by applying current pulses in drawing process. The work-hardening behavior of the multi-courses drawing deformation can be well described by Hollomon formula σ=κΕn. With the application of current pulses in drawing deformation, the work-hardening exponents of H0Cr17Ni6Mn3 steel wires and 1Cr18Ni9 stainless steel wires were reduced by 33% and 45%, respectively, and their work-hardening coefficients were reduced by 41% and 47%, respectively. It was also found that the work-hardening coefficient of wires was reduced with the increment of the frequency of current pulses, while the work-hardening exponents of both steels were insensitive to the pulsing frequency.
