蒸汽焓流量计量标准实验研究

Experimental Study on the Steam Enthalpy Flux Measurement Standard

工业蒸汽的热能计量需要解决干度测量和热能相关量值溯源等计量基础问题。在本文中,研究了焓流量计量标准蒸汽源。阐述了蒸汽焓流量的计量方法,基于热力学建立了蒸汽源焓流量与干度等参数量值确定的理论模型。介绍了焓流量计量标准实验装置的组成、对过热蒸汽加湿以获得湿蒸汽的设计方案和温度、压力、流量参数的测量方法。本装置可在DN50和DN80管路提供0.3～0.9 MPa、7～70 m/s的过热蒸汽流和0.85～1.00干度的饱和蒸气流,并能确定蒸汽源的干度、质量流量和体积流量、焓流量等量值,焓流量、干度和流量稳定性分别优于2%、0.5%和2%,扩展不确定度分别为0.8%、1%和0.5%。对实验装置性能和实验结果进行了讨论。该装置可用于蒸汽热能计量仪表的模型研究和性能试验。

The enthalpy flux measurement for industrial water steam has been facing the problems of the dryness fraction measurement and the relative quantities traceability. The steam calibration source of the enthalpy flux was studied. The general measurement method for steam enthalpy flux was described. Based on thermodynamics the models for determination of dryness fraction, enthalpy flux, etc. were established. The composing of the enthalpy flux calibration source, the scheme for wetting the superheated steam and the means of temperature, pressure and flow rate measurements were presented. The facility with the DN50 and DNS0 pipes provides the saturated steam of the dryness fraction of 0.85 - 1.00 or superheated steam, are of 0.3 - 0.9 MPa and 7 - 70 m/s respectively. The enthalpy flux, dryness fraction and mass flow of the steam can be obtained with the short - term stabilities less than 2%, 0.5% and 2% respectively and with the uncertainties of 0.8%, 1% and 0.5% respectively. The facility performance and the experimental results were discussed. This facility can be utilized for the research and development of steam measuring instruments.