唐山矿卷帘风窗自动控制调风系统

为了避免带式输送机火灾时产生的烟流进入各工作面,防止灾害面积扩大,设计了一种PLC自动控制卷帘风窗调风系统。根据现场实际情况及风窗风量调节的可行性,通过双烟雾、双CO传感器和双向风速传感器对火灾烟流实时数据的采集,并与预先设定的极限值相比较,实现了自动调节卷帘风窗面积大小,达到了灾变风流的自动引流功能,提高了带式输送机火灾时矿井的抗灾能力。

低氮燃烧智能调风控制系统对锅炉运行的深度优化

锅炉进行低氮燃烧改造后,为了在降低NOx排放的同时达到最佳的燃烧效果,改变以往根据经验进行配风控制的运行管理,提高运行经济性,为锅炉配备了低氮燃烧智能调风控制系统。运行效果证明:低氮燃烧智能调风控制系统能在一定程度上降低NOx排放量,提高燃烧效率,从而实现锅炉在低氮燃烧改造后环保及经济指标的进一步优化。

建庄煤矿智能通风系统研究与优化

针对建庄矿业现有通风系统实时监测性差、远程控制功能弱、风量调节自动化水平低等问题,以井下风机智能控制、风门和风窗远程监测调控为目标,建设了包括矿井通风智能化软件平台,主要通风机、局部通风机、风门和风窗调风系统的智控一体的通风系统,实现了风网实时解算,测风无人化,风网风量调控自动化,井下实时监测与远程控制,风网、风门和通风机调控自动化、智能化,并具备灾害预警与防控等功能。该系统整体表现优越,显著提高了煤矿通风系统的自动化和智能化水平。

Effects of atmospheric pressure fluctuations on hill-side coal fires and surface anomalies

This paper presents numerical studies on the effects of atmospheric pressure fluctuations on hill-side coal fires and their surface anomalies. Based on the single-particle reaction–diffusion model, a formula to estimate oxygen consumption rate at high temperature controlled by oxygen transport is proposed.Daily fluctuant atmospheric pressure was imposed on boundaries, including the abandoned gallery and cracks. Simulated results show that the effects of atmospheric pressure fluctuations on coal fires and surface anomalies depend on two factors: the fluctuant amplitude and the pressure difference between inlet(s) and outlet(s) of the air ventilation system. If the pressure difference is close to the fluctuant amplitude, atmospheric pressure fluctuations greatly enhance gas flow motion and temperatures of the combustion zone and outtake(s). If the pressure difference is much larger than the fluctuant amplitude, atmospheric pressure fluctuations exert no impact on underground coal fires and surface anomalies.

Prediction and optimization of aerodynamic noise in an automotive air conditioning centrifugal fan

The high aerodynamic noise induced by automotive air conditioning systems has important effects on the ride comfort, and the centrifugal fan is the largest noise source in these systems. It is very important to reduce the aerodynamic noise generated by the centrifugal fan. The flow field and the sound field on the whole centrifugal fan configuration have been carried out using the computational fluid dynamics. Simulation results show that the sound pressure level near the outlet of the centrifugal fan is too high. Based on the relationship between flow characteristics and the aerodynamic noise, four parameters of the centrifugal fan, i.e., impeller blade＇s outlet angle 0, volute tongue＇s gap t, collector inclination angle fl, and rotating speed n, were selected as design variables and optimized using response surface methodology. While keeping the function of flow rate unchanged, the peak noise level is reduced by 8 dB or 10.8%. The noise level is satisfactorily reduced.

Genetic Optimization Algorithm of PID Decoupling Control for VAV Air-Conditioning System

Variable-air-volume (VAV) air-conditioning system is a multi-variable system and has multi coupling control loops. While all of the control loops are working together, they interfere and influence each other. A multivariable decoupling PID controller is designed for VAV air-conditioning system. Diagonal matrix decoupling method is employed to eliminate the coupling between the loop of supply air temperature and that of thermal-space air temperature. The PID controller parameters are optimized by means of an improved genetic algorithm in floating point representations to obtain better performance. The population in the improved genetic algorithm mutates before crossover, which is helpful for the convergence. Additionally the micro mutation algorithm is proposed and applied to improve the convergence during the later evolution. To search the best parameters, the optimized parameters ranges should be amplified 10 times the initial ideal parameters. The simulation and experiment results show that the decoupling control system is effective and feasible. The method can overcome the strong coupling feature of the system and has shorter governing time and less over-shoot than non-optimization PID control.

Analysis of grid-connected voltage stability of FSCWT based on bifurcation theory

This paper studies on the change mechanisms of the voltage stability caused by the grid connection of front-end speed-controlled wind turbines(FSCWT)integrating into power system.First of all,the differential algebraic equations describing the dynamic characteristics of wind turbines are illustrated.Then,under the guidance of IEEE3 node system model,the influence of the angular velocity of wind turbines,the reactive power and the active power at load bus on the voltage stability of grid-connection has been analyzed by using bifurcation theory.Finally,the method of linear-state feedback control has been applied to the original system in accordance with the bifurcation phenomenon of grid-connected voltage caused by the increase in the active power at load bus.Research shows that voltage at the grid-connected point would be changed with the fluctuation of turbines angular velocity.And increasing its reactive power can enhance voltage at the grid-connected point;problem of bifurcation at the grid-connected point can be delayed when increasing the gain k s of feedback controller within a certain range.

Design of Control Scheme for Variable Air Volume Air- conditioning System

The air quantity of variable air volume system for the rooms and the total air quantity of the system changes with the change of room load. Combined with the system composition in the laboratory, the paper determines the control scheme of the variable air volume system, that is, indoor temperature-control, indoor positive pressure control, air distribution static pressure control, air-supply temperature control and new air volume control. The dotted lines with arrows mean the output signals from the control unit to actuator, and the solid lines with arrows represent the input signals from the actuator to the control unit.

The Applications of High-voltage variable frequency speed regulation System in Main Exhauster of Sintering

Main Exhauster is one of the main equipment of sintering production. It needs to consume a lot of electricity. Therefore, the system＇ s reconstruction for energy-saving will effectively reduce electricity for the production. The paper takes an iron and steel enterprise that had successfully transformed the synchronous motors of main exhauster of sintering as an example, which describes the application of high-voltage variable frequency speed regulation system in main exhauster of Sintering, so as to provide a reference for other iron and steel enterprises.

Evaluation on Snow Infiltration into Heating Ventilation and Air Conditioning Intake： A Numerical Study

A HVAC （heating ventilating and air conditioning） system is generally designed to ventilate an indoor space. In windy and snowy climates dispersed snow particles in ambient air can enter the intake duct, potentially causing a serious problem. The study addresses the influence of suction volumetric flow rates, the potential discrepancy of snow intake based upon the wind direction in relation to the intake vent, and the possible difference in amounts of infiltrated snow particles in varying intake vent design and locations. The necessary characteristic quantities are defined. The simulation results show the rate of infiltration and the efficiency of the chosen intake designs. The magnitude and direction of wind influences snow infiltration significantly. The daily amount of infiltrated snow is introduced to be the characteristic measure of the infiltration in design of the HVAC systems.

Wind Generation Modeling for Transmission Systems Adequacy Studies with Economic Dispatch

In this paper, a strategy is proposed in order to introduce in a realistic way wind generation into a HL11 （bulk power system） non sequential Monte Carlo adequacy study with economic dispatch. Thanks to the implemented solution, wind generation is consequently confronted to operational constraints related to high powered thermal units, nuclear parks or thermal machines with technical minimum value. Moreover, during each simulated system state, a DC load flow is also calculated in order to evaluate reinforcements optimizing the large scale integration of wind power production. The simulation tool modified during the present work is called Scanner and is the property of Tractebel Engineering （Gaz de France-Suez） company. It has been here applied to an academic test system： the Roy Billinton Test System （RBTS）.

Performance research and optimization on the fan test system based on experiment

To investigate the fan performance of air conditioning system, two different configuration fan test systems are designed. All scale simulation of the two systems provide the basis for design and improvement of air conditioning system fans to improve the internal flow, increase air volume, and reduce the noise. The conclusion that disturbance on flow of nuzzle outlet is the main sources of measurement error about 5% can be proved by the comparative analysis of the results between computation and experiment. Through Optimization Design of Partial Structure they all meet the industry standard, measurement error less than 1.5%.