Men Xiuhua

The denoise design of pressure reducing control valve in thermal power plant

Noises are common during operation, so the noise analysis and noise removal is necessary. High level vibration and noise may lead to the control valve fully open. After analyzing the causes of vibration and noise, the noise estimation formula put forward by Masonneilan company is used to estimate noise, and two measures of pipeline modification and valve internal constitution reform are proposed. In the valve internal structure reform design, the reform is mainly focused on designing balance spool, designing and installing sleeves and limiting spool motion. The pressure experiment results show that the performance of control valve is better.

A new method for the analysis of temperature-dependent resistances and inductances of multiconductor cable

The whole mechanical test procession, especially transmission cable is effected evidently by environment temperature fluctuation. So of particular interest in the paper is to discuss the resistance and inductance parameters of multiconductor at environment of changing temperature. A new approach with the given formulas is presented to calculate electric parameters using finite element method. And then, the temperature-dependent characteristics of resistance and inductance are obtained, which are agreed with the result obtained by energy method. The change of equivalent current density for multiconductor also highlights the parameters change when proximate effect is considered. The result is shown that the temperature-dependent parameters bring more important responses on the terminal of circuit network containing certain deviation. It is shown that. For the first time, results are shown for the lossy transmission cable with temperature-dependent parameters characteristic, which are used to quantify the main practical engineering.