为了使可听噪声的时域结果直接应用于噪声评价中,根据声级计的基本原理和直流电晕放电产生可听噪声的随机性特点,叙述了将可听噪声时域测量结果转化为声压级的方法,即采用功率谱分析方法来计算可听噪声声压的有效值,同时实现对噪声信号进行时间计权、A计权及倍频分析等,从而实现了由时域数据获得频域声压级的目的。基于实验室内搭建的单点电晕放电可听噪声测试平台,获得了单点电晕放电产生的可听噪声的时域波形,将该方法与Labview噪声分析工具箱的分析结果进行对比,验证了本文方法的正确性。最后对单点电晕放电产生可听噪声的频域特性及声压级特性进行了分析。研究结果表明,单点直流电晕放电产生的可听噪声的声压级在可听的频率范围内(20 Hz^20 k Hz),随着电压增加而有所增加;电晕噪声在高频段(1 k Hz以上)内的A计权声压级相对较大。研究方法和所得结论可为对电晕放电产生可听噪声特性的深入研究奠定基础。
A novel two-dimensional （2D） simulation method of positive corona current pulses is proposed. A control-volume- based finite element method （CV-FEM） is used to solve continuity equations, and the Galerkin finite element method （FEM） is used to solve Poisson＇s equation. In the proposed method, photoionization is considered by adopting an exact Helmholtz photoionization model. Furthermore, fully implicit discretization and variable time step are used to ensure the time-efficiency of the present method. Finally, the method is applied to a positive rod-plane corona problem. The numerical results are in agreement with the experimental results, and the validity of the proposed method is verified.
