空调空气幕风叶轮片级进模设计

分析了空调空气幕风叶轮片的成形工艺特点,对排样方案和模具结构进行了设计,介绍了模具结构的主要特点及其工作原理,详细描述了模具主要零件的结构,包括凸模、凹模、卸料板和凸模固定板,并提出了保护小凸模的有效方法。实际生产表明,该排样方案和模具结构合理有效,延长了模具的使用寿命,为生产类似产品提供了参考。

萝茨鼓风机风叶轮渐开线轮廓刨削加工工艺与胎具设计

结合萝茨鼓风机风叶轮渐开线表面的成型原理和生产制造工艺的特点,在普通牛头刨床上,利用展成运动原理对渐开线表面加工的刀具几何形状进行了分析计算、设计及胎具设计,并在生产实践中得到了应用,取得了较好的应用价值和经济效益,是利用普通机床设计专用工装夹具用于批量生产的一种有效方法.

风叶轮叶片插销自动包边工艺研究与应用

本文介绍了我司风叶轮叶片插销包边工艺的现状,并针对现有工艺的缺点,组织设计与制造了叶片插销自动包边专用设备,并进行了叶片插销自动包边工艺的研究与应用,有效地解决了叶片插销包边劳动强度大、生产效率低、质量不稳定等问题。

TXLF01风叶轮裂纹的形成与防止

通过对TXLF01风叶轮铸件结构特点的分析，结合铸造生产实际，以合金凝固理论为基础，对铸件裂纹形成机理进行了分析，提出减小液膜厚度、细化晶粒以提高抗裂强度，从而解决风叶轮铸件裂纹缺陷问题。

轴流风机效率降低问题分析与处理

分析了轴流风机在批量生产时出现静压效率下降和风机静压降低的原因,提出了诸如调整叶轮与风筒间隙、改进制造工艺等一系列合理的措施,保证了该类风机静压效率及风机静压达到样机水平,并确保风机性能稳定。

JE13型风速校验平台在风速现场校准量值溯源中的应用

由于现行风速传感器现场校准方法和标准设备的工作原理等原因,使得自动气象站风速现场校准量值无法进行溯源。本文利用JE13型风速校验平台,并使用一个中间传递用的风速传感器和数字式叶轮风表,实现自动气象站风速传感器的现场校准量值溯源到实验室大型风洞标准装置上。

Numerical investigation on the flow and power of small-sized multi-bladed straight Darrieus wind turbine

Straight Darrieus wind turbine has attractive characteristics such as the ability to accept wind from random direction and easy installation and maintenance. But its aerodynamic performance is very complicated,especially for the existence of dynamic stall. How to get better aerodynamic performance arouses lots of interests in the design procedure of a straight Darrieus wind turbine. In this paper,mainly the effects of number of blades and tip speed ratio are discussed. Based on the numerical investigation,an assumed asymmetric straight Darrieus wind turbine is proposed to improve the averaged power coefficient. As to the numerical method,the flow around the turbine is simulated by solving the 2D unsteady Navier-Stokes equation combined with continuous equation. The time marching method on a body-fitted coordinate system based on MAC (Marker-and-Cell) method is used. O-type grid is generated for the whole calculation domain. The characteristics of tangential and normal force are discussed related with dynamic stall of the blade. Averaged power coefficient per period of rotating is calculated to evaluate the eligibility of the turbine.

Fluent-based numerical simulation of flow centrifugal fan

Testing centrifugal fan flow field by physical laboratory is difficult because the testing system is complex and the workload is heavy, and the results observed by naked-eye deviates far from the actual value. To address this problem, the computational fluid dynamics software FLUENT was applied to establish three-dimensional model of the centrifugal fan. The numeral model was verified by comparing simulation data to experimental data. The pressure centrifugal fan and the speed changes in distribution in centrifugal fan was simulated by computational fluid dynamics soft-ware FLUENT. The simulation results show that the gas flow velocity in the impeller increases with impeller radius increase. Static pressure gradually increases when gas from the fan access is imported through fan impeller leaving fans.

Effect of blade pitch angle on aerodynamic performance of straight-bladed vertical axis wind turbine

Wind energy is one of the most promising renewable energy sources, straight-bladed vertical axis wind turbine(S-VAWT) appears to be particularly promising for the shortage of fossil fuel reserves owing to its distinct advantages, but suffers from poor self-starting and low power coefficient. Variable-pitch method was recognized as an attractive solution to performance improvement, thus majority efforts had been devoted into blade pitch angle effect on aerodynamic performance. Taken into account the local flow field of S-VAWT, mathematical model was built to analyze the relationship between power outputs and pitch angle. Numerical simulations on static and dynamic performances of blade were carried out and optimized pitch angle along the rotor were presented. Comparative analyses of fixed pitch and variable-pitch S-VAWT were conducted, and a considerable improvement of the performance was obtained by the optimized blade pitch angle, in particular, a relative increase of the power coefficient by more than 19.3%. It is further demonstrated that the self-starting is greatly improved with the optimized blade pitch angle.

Static and Dynamic Study of a Wind Turbine Blade with Horizontal Axis

In this work the authors present a calculation process of the blades for wind turbine with horizontal axis. It is about a blade discretized by the finite element method （FEM） in order to determine the gyroscopic effect during its rotation at a high speed. A blade must have the maximum output and resist to aerodynamic loads distributed over its length, which are related to its geometrical characteristics and the speed of the wind. For that, the authors wrote the relations whom determine these loads according to the flow speed of the wind, then, the authors integrated them in the laws of structure mechanics to obtain the motion equations of the blade. This process was applied to a twisted blade with a length of 1.9 m, built out of pressed aluminum sheet with a profile of the type NACA; this profile gives the best aerodynamic output. This blade is an element of a three-bladed propeller for wind turbine of maximum power 5 kW. Finally, we visualized its deformations and then the authors checked its holding in service.

Airfoil effects on efficiency of 2 MW horizontal axis wind turbine blades

Optimization of airfoil characteristics such as lift and drag is essential for high efficiency wind turbine blade design. In this research, effects of airfoil lift and drag on blade power coefficients were investigated by using of wind turbine blade design software, PROPID. Firstly, a wind turbine blade of 2MW class was designed with DU-serics airfoils in the inner part and with aNACA series airfoil as a main airfoil in the outer part. Lift distribution was set to have near L/D maximum at each span station. Then, lift and drag curves were modified to observe effect of L/D variation. Drag and lift change with constant L/D on blade power coefficient was also studied for sensitivity investigation. Each case was optimized with Newtonian iteration incorporated in PROPID. High design lift coefficient results in less chord length and twist angle to maintain same aerodynamic load level. And, power coefficient wasn＇t improved much with high L/D. During the process, optimal inputs such as lift distribution, design lift and induction factors were suggested. As results, it was found that L/D maximization was important to obtain high efficiency. For the L/D maximization, lift maximization was important to minimize structural weight, but decreasing drag didn＇t affect the blade shape.

Parametric geometry representations for wind turbine blade shapes

Based on the Joukowsky transformation and Theodorsen method, a novel parametric function （shape function） for wind turbine airfoils has been developed. The airfoil design space and shape control equations also have been studied. Results of the analysis of a typical wind turbine airfoil are shown to illustrate the evaluation process and to demonstrate the rate of convergence of the geometric characteristics. The coordinates and aerodynamic performance of approximate airfoils is rapidly close to the baseline airfoil corresponding to increasing orders of polynomial. Comparison of the RFOIL prediction and experimental results for the baseline airfoil generally show good agreement. A universal method for three-dimensional blade integration-＂ Shape function/Distribution function＂ is presented. By changing the parameters of shape function and distribution functions, a three dimensional blade can be designed and then transformed into the physical space in which the actual geometry is defined. Application of this method to a wind turbine blade is presented and the differences of power performance between the represented blade and original one are less than 0. 5%. This method is particularly simple and convenient for bodies of streamline forms.

Application of Active Damping Control Using Piezoelectric Material in Modeling of a Wind Turbine Blade

On the basic of passive damping control, we do modeling and simulating in another approach to improve the vibration alleviating effect, the piezoelectric layer damping （PLD）, which is called active control. The piezoelectric damping patches are under control of PID controller （matlab simulating） in voltage defference. Here, we use the software PRO/ENGINEER to design and model a wind turbine blade before using COMSOL to simulate the dynamic motion of the wind turbine blade and its interaction with aerodynamic force of wind in finite element method. Some different models are built-- the original turbine blade and the turbine blade with damping patches on different location and quantity. Then, according to the simulation results, we compare the effects of passive and active damping control, also the effect of patches locations and quantities under different wind speed. This research can provide a direction for future study about ways to decrease vibration of turbine blades.

具有发电消音功能的桥梁挡风屏的设计说明

众所周知,较大的风荷载不仅对桥上行驶的车辆产生巨大的噪音,对其安全都会构成一定的威胁;横风是高速车辆的威胁之一,高速车辆在横风的作用力下,具有发生倾覆的危险,强风作用严重限制了车辆的运行速度。同时,风力也是一种能量,公路桥梁的上风力一般较大,对通过桥梁上的风能不能充分利用,也是一种浪费。为保持车行驶的稳定性,同时充分通过桥梁上的风能,作者设计出了具有发电消音功能的桥梁挡风屏,具有结构复杂。

Optimal Design of Splitters Attached to Turbo Blower Impeller by RSM

This paper describes the optimization of the impeller having splitters for a turbo blower.Two design variables,chord of splitter and pitch of splitter,are introduced to enhance the blower performance.Blower pressure and ef-ficiency are selected as an object function,and the optimization of the blower impeller is performed by a response surface method (RSM).Three-dimensional Navier-Stokes equations are introduced to analyze the internal flow of the blower and to find the value of the object function for each case.Throughout the shape optimization of the splitters attached to the impeller in the turbo blower,pressure and efficiency at the design flow condition are suc-cessively increased by 5.9 percent and 17.9 percent respectively based on the reference blower.The higher blower efficiency obtained by optimization of impeller having splitters is mainly caused by reducing the number of im-peller blades and optimal design of splitters in the blade passage while pressure increase keeps almost the same with the reference blower.For the object function of pressure,pressure increase is obtained at the design and off-design conditions while efficiency keeps higher compared to the reference blower.The enhancement of blow-er performance is due to the reduction of reverse and circulation flows in the blade passage.

Numerical Simulation on Effects of Pressure Distribution of Wind Turbine Blade with a Tip Vane

It is important to study the pressure distribution on the blade and in the adjacent area while searching the power augmentation theory with adding a tip vane to the wind turbine. This paper shows the CFD simulation relationship of the pressure distribution on the rotor blade and in the adjacent area, after calculating the pressure of the different chordwise and spanwise point on the blade with the tip vane-V（8.8×8） and without the tip vane under tip speed ratio λ 4.5. Combining the isobaric section figure in certain location, it can be seen that the tip vane improve the pressure difference between pressure and suction surface. The most influenced zone is found and these can further display the power augmentation theory of the wind turbine using the tip vane. The simulation calculation was based on N-S equations. 3-D, steady, implicit solver was chosen. Turbulence model was k-ω SST. Discretization scheme is SECOND ORDER UPWIND. Pressure-velocity coupling was a typical SIMPLE scheme. In the whole grid system, two-divided grid formation was adopted, that is, inner region and outer region. Inner region including rectangular solid blade and neighboring, outer region is semi-cylinder. There were together 720,000 nodes with tetra-prism unstructured mesh.

Heat Transfer and Performance Characteristics of Axial Cooling Fans with Downstream Guide Vanes

This study examines experimentally the effect of stators on the performance and heat transfer characteristics of small axial cooling fans. A single fan impeller, followed by nine stator blades in the case of a complete stage, was used for all the experimental configurations. Performance measurements were carried out in a constant speed stage performance test rig while the transient liquid crystal technique was used for the heat transfer measurements. Full surface heat transfer coefficient distributions were obtained by recording the temperature history of liquid crystals on a target plate. The experimental data indicated that the results are highly affected by the flow conditions at the fan outlet. Stators can be beneficial in terms of pressure drop and efficiency, and thus more economical operation, as well as, in the local heat transfer distribution at the wake of the stator blades if the fan is installed very close to the cooling object. However, as the separation distance increases, enhanced heat transfer rate in the order of 25% is observed in the case of the fan impeller.

Numerical analysis and experimental investigation of wind turbine blades with innovative features:Structural response and characteristics

Innovative features of wind turbine blades with flatback at inboard region,thick airfoils at inboard as well as mid-span region and transversely stepped thickness in spar caps have been proposed by Institute of Engineering Thermophysics,Chinese Academy of Sciences(IET-Wind)in order to improve both aerodynamic and structural efficiency of rotor blades.To verify the proposed design concepts,this study first presented numerical analysis using finite element method to clarify the effect of flatback on local buckling strength of the inboard region.Blade models with various loading cases,inboard configurations,and core materials were comparatively studied.Furthermore,a prototype blade incorporated with innovative features was manufactured and tested under static bending loads to investigate its structural response and characteristics.It was found that rotor blades with flatback exhibited favorable local buckling strength at the inboard region compared with those with conventional sharp trailing edge when low-density PVC foam was used.The prototype blade showed linear behavior under extreme loads in spar caps,aft panels,shear web and flatback near the maximum chord which is usually susceptible to buckling in the blades according to traditional designs.The inboard region of the blade showed exceptional load-carrying capacity as it survived420%extreme loads in the experiment.Through this study,potential structural advantages by applying proposed structural features to large composite blades of multi-megawatt wind turbines were addressed.

Optimal Operation of Turbo Blowers Serially Connected Using Inlet Vanes

Optimal operation of the turbo blowers having an inlet vane has been studied to understand the blowers' operating performance.To analyze three-dimensional flow field in the turbo blowers serially connected,general analysis code,CFX,is introduced in the present work.SST turbulence model is employed to estimate the eddy viscosity.Throughout the numerical analysis,it is found that the flow rates of the turbo blowers can be controlled at the vane angle between 90 (full open condition) degrees and 60 degrees effectively,because pressure loss rapidly increases below 60 degree of a vane angle.Efficiency also has almost the same values from 90 degrees to 60 degrees of a vane angle.It is noted that the distorted inlet velocity generated in the small vane angle makes performance deterioration of the turbo blowers due to the local leading edge separation and the following non-uniform blade loading.

Analysis of Aerodynamic Load on Straight-bladed Vertical Axis Wind Turbine

This paper presents a wind tunnel experiment for the evaluation of energy performance and aerodynamic forces acting on a small straight-bladed vertical axis wind turbine(VAWT) depending on several values of tip speed ratio. In the present study, the wind turbine is a four-bladed VAWT. The test airfoil of blade is symmetry airfoil(NACA0021) with 32 pressure ports used for the pressure measurements on blade surface. Based on the pressure distributions which are acted on the surface of rotor blade measured during rotation by multiport pressure-scanner mounted on a hub, the power, tangential force, lift and drag coefficients which are obtained by pressure distribution are discussed as a function of azimuthally position. And then, the loads which are applied to the entire wind turbine are compared with the experiment data of pressure distribution. As a result, it is clarified that aerodynamic forces take maximum value when the blade is moving to upstream side, and become small and smooth at downstream side. The power and torque coefficients which are based on the pressure distribution are larger than that by torque meter.