气动式波浪发电透平的设计模型

分析了气动式波浪发电透平的特点、运行环境以及透平与振荡气流之间的相互作用过程,提出了描述透平稳态特性和动态特性的参数以及描述透平运动性能的特性曲线,推导得出透平的稳态最佳工作点,最后提出了透平的匹配设计方法。该设计模型的建立,对波浪透平的研究和设计具有较重要的指导意义     

汕尾市100kW波力电站空气透平与气室匹配设计

根据用1/15模型,在造波水槽中进行试验获得气室的Δ Pi- Q、ηA- Q、 NA- Q特性,以及用300mm透平模型,在1000mm活塞式往复流透平试验台进行试验获得的对称翼透平、双向固定导叶冲动透平和双向自调节导叶冲动透平的CP-、ηT-特性,进行了气室与三种空气透平的匹配设计。表明在设计波况下,采用1.025m的双向自调节导叶冲动透平时,ηT·ηA达50.43%;采用0.975m的双向自调节导叶冲动透平时,ηT·ηA达46.66%;采用0.975m的双向固定导叶冲动透平时,ηT·ηA达33.66%;采用1.45m对称翼透平时,ηT·ηA仅为29.9%。并对四种不同匹配方案进行了对比分析。     

振荡水柱波能装置冲击式空气透平优化数值模拟研究

冲击式空气透平是振荡水柱式波能发电装置的二级能量转换装置,具有自启动性能好、在大流量系数区保持较高效率等优势,近年来应用越来越广泛.有学者提出在冲击式透平动叶片尖端安装环结构的设计,可以改善动叶片叶尖间隙处的气流流动形态,提高透平的工作性能.依托于此观点,构建了安装有环结构的冲击式透平的三维定常数值模型,并通过网格数量...     

非定常条件下OWC径向透平冲击式动叶片优化研究

为优化径向透平动叶片的结构型式,有效提高透平工作效率,本文基于Ansys-Fluent软件构建振荡水柱波能发电装置径向冲击式透平的三维瞬态全流域数值模型,通过改变透平动叶片吸力面型式,研究了正弦往复入射气流条件下动叶片厚度差异对透平扭矩、压强等参量的影响及其对透平输入系数、扭矩系数和周期平均效率等非定常性能评价参数的影响。在保证压力面型式不变情况下,研究了5种动叶片厚度分别为7 mm、13 mm、16 mm、19 mm和22 mm的透平在呼气、吸气阶段的非定常工作性能,结果表明：不同动叶片厚度的透平的非定常工作性能存在较大差异,动叶片厚度为13 mm的透平非定常工作性能最优,最大峰值效率可达47.7%。     

带空气透平的后弯管浮式防波堤实验研究

针对海工作业平台、海洋养殖网箱等海洋装备的安全防护问题,提出了一种带空气透平的后弯管浮式防波堤,该空气透平既可将作用在防波堤上的波浪能转化成机械能并用于发电,还可显著减小防波堤的锚链力。在介绍了防波堤原理和结构特点的基础上,设计了物理实验模型,并在实验室造波池内进行了模型试验,研究了波浪周期、波高、吃水深度与弯管数量等因素对后弯管浮式防波堤透射系数和锚链力的影响规律。研究结果表明,波浪周期越短,波高越低,防波堤的透射系数越小,锚 链力越小,其消波性能优于传统的浮式防波堤.     

稳态流动中对称翼透平的空气动力性能

本文对12个不同设计参数的对称翼型透平模型进行了实验研究,获得了其在0°～90°迎角范围的空气动力特性曲线及效率曲线。根据试验结果,分析了设计参数对透平性能的影响,发现了失速区透平力系数的非单位特性。本文的结果可以供透平设计及改善透平性能时使用,在进行波能系统分析时,也可作为透平的传递函数。     

用于振荡水柱波能系统的径流式空气透平数值模拟研究

径流式空气透平是振荡水柱式波能发电系统的二级能量转换装置,因其具有结构简单、输出扭矩大、轴向推力小的优势,得到了越来越多的关注。采用计算流体力学软件Ansys-Fluent 12.0,通过数值模拟方法考察了不同转子叶片稠度对径流式空气透平定常无量纲评价参数的影响规律。研究结果表明:虽然径流式透平可在双向气流下实现单向旋转,但当气流通过方向不同时,透平的定常工作性能存在明显差异,这与传统轴流式透平完全不同;此外,稠度对透平效率的影响在不同流量系数范围内也不同。因此,综合考虑气流流向、透平整个工作范围内输出效率,推荐采用的转子叶片稠度为2.34。     

往复流中双向导向叶冲动透平模型性能试验研究

研制了 30 0双向自调导叶透平试验机组 ,安装在 10 0 0活塞式往复流透平试验台上 ,对两种叶轮方案和 6种不同喷咀、扩压器进行了不同活塞行程、不同周期和不同恒定输出电压下性能试验。试验结果表明在喷咀出口角α1=2 1 5°、扩压器入口角α2 =6 5 5°和α1=2 4°、α2 =6 3°组合最佳 ,最高效率达 5 3 3% ,而且在宽广流量系数范围内 ,特别是大流量系数范围内都有较高效率。大大优于常用对称翼透平。将上下游导叶固定 ,变成双向固定导叶透平。用No 1叶轮和 6种导叶出口角组合进行试验。表明最佳导叶出口角为 2 4°～ 30°,最高效率仍达 38 5 % ,比对称翼透平仍高许多     

波浪发电用对向流翼笼式透平的实验研究

一种自行研制的新型波浪发电装置—对向流、翼笼式、低参数透平［１］。该透平具有独特的壳体,能使叶轮在对向气流通过时作定向旋转,从而带动发电机发电。实验证明该机运转可靠、效率高,又具有结构简单、易于制造、寿命长、成本低等优点。用于海上浮标灯的波浪发电装置,与发电机匹配好,且容易起动。还阐述了波浪发电装置的效率分析与计算,以及活塞实验研究、水池模拟实验和海上实验结果。     

威尔斯透平设计原理探讨

威尔斯透平的特征是能工作于交变气流中。本文根据串列翼栅的风洞试验性能导出了该翼栅于交变气流中的性能,从而,工作于交变气流中的威尔斯透平就能处理为工作于单向气流中。在此基础上探讨了威尔斯透平的设计原理,如最佳效率及与获得最佳效率相适应的威尔斯透平设计方法。     

IPN turbines: A source of underwater power

The effect of hydrostatic pressure on the basic performance of a simple isopropyl nitrate (IPN) power turbine is discussed, with particular reference to the choice of suitable design parameters for systems operating at depths down to 3100 ft. It is shown that the decomposition heat energy available from a perfect turbine system decreaseswith increasing depth, from 19·9 kWh/ft³ at sea level to 2·34 kWh/ft³ for a critical pressure ratio design. Approximately two-thirds of this energy may be recoverable in a practical system as usable power on the sea bed.     

OWC装置空气透平压降作用试验研究

空气透平的压降作用及由其带来的空气流速变化,是串联2次能量转换过程、实现两转换过程耦合的核心要素.试验主要是在物理模型的基础上,对带有冲击式透平的OWC装置能量转换影响因素进行研究.试验主要考察2次能量转换耦合作用下,气室内自由水面变换、气室内压强变化、输气管内空气流速变换及三者耦合与相互作用.     

Self-Starting Analysis of an OWC Axial Impulse Turbine in Constant Flows: Experimental and Numerical Studies

In recent times, self-rectifying axial-flow air turbines are being widely employed in oscillating water column (OWC) wave energy converters (WEC). The steady performance of air turbines has been systematically investigated in previous studies. However, there still exists a lack of information on their unsteady performance, such as in the self-starting characteristics and subsequent running behavior. In this study, the unsteady behavior of impulse turbine under various constant-flow conditions is investigated. Experimental studies were conducted to investigate the effects of constant-load on the variations in the rotation speed, the pressure drop and the torque output of the turbine starting from rest. A fully passive flow-driving numerical model is employed for further detailed analysis of the flow and pressure fields. Followed by a well-agreed validation using the corresponding experimental data, the three dimensional (3D) transient model is used to study the effects of the air-flow velocity magnitude and the rotors’ moment of inertia on the self-starting performance of the turbine. Except for the variations in the rotation speed, the pressure drop and the pneumatic torque, the distributions of the flow-field and the pressure over the blades at specific time-points are analyzed.     

Numerical modeling of a wave energy converter based on U-shaped interior oscillating water column

The paper presents a concept of a wave energy converter and the numerical model to calculate the hydrodynamic responses in waves and the power produced by the power take off system. The system consists of an asymmetric floater with an interior U-tank partially filled with water and two lateral air chambers connected by a duct. The motion of the U-shaped oscillating water column, mainly induced by the rolling of the floater, forces the air through the duct where a Wells turbine is installed to absorb the wave energy.The wave-floater hydrodynamics is calculated with a Green's function panel method, while the oscillating water column motions hydro-mechanics are derived from the one-dimensional Euler's equation. The dynamics of the Wells turbine is realistically represented by one additional differential equation on the unknown air pressure fluctuation. This equation is derived assuming small amplitude motions of the water column and assuming the linear isentropic relation is valid for the air thermodynamics in the air chambers. The Wells turbine is characterized by a drastic drop of efficiency above a critical pressure value due to stalling on the blades. The effect of a by-pass valve to prevent stalling is introduced in the numerical model in a simplistic way. The numerical model is implemented and tested for a wave energy converter with a displacement of 1150 t, including 490 t for the interior water column, and an installed turbine with 2.3 m of diameter. An analysis of the influence of changing different design parameters on the system efficiency is also presented.     

Effects of Rotor Solidity on the Performance of Impulse Turbine for OWC Wave Energy Converter

Impulse turbine, working as a typical self-rectifying turbine, is recently utilized for the oscillating water column (OWC) wave energy converters, which can rotate in the same direction under the bi-directional air flows. A numerical model established in Fluent is validated by the corresponding experimental results. The flow fields, pressure distribution and dimensionless evaluating coefficients can be calculated and analyzed. Effects of the rotor solidity varying with the change of blade number are investigated and the suitable solidity value is recommended for different flow coefficients.     

Numerical and Experimental Study of the 3D Effect on Connecting Arm of Vertical Axis Tidal Current Turbine

Vertical axis tidal current turbine is a promising device to extract energy from ocean current. One of the important components of the turbine is the connecting arm, which can bring about a significant effect on the pressure distribution along the span of the turbine blade, herein we call it 3D effect. However, so far the effect is rarely reported in the research, moreover, in numerical simulation. In the present study, a 3D numerical model of the turbine with the connecting arm was developed by using FLUENT software compiling the UDF (User Defined Function) command. The simulation results show that the pressure distribution along the span of blade with the connecting arm model is significantly different from those without the connecting arm. To facilitate the validation of numerical model, the laboratory experiment has been carried out by using three different types of NACA aerofoil connecting arm and circle section connecting arm. And results show that the turbine with NACA0012 connecting arm has the best start-up performance which is 0.346 m/s and the peak point of power conversion coefficient is around 0.33. A further study has been performed and a conclusion is drawn that the aerofoil and thickness of connecting arm are the most important factors on the power conversion coefficient of the vertical axis tidal current turbine.     

波浪作用下基于不同负载的一种Savonius型水轮机捕能性能研究

通过水轮机捕能是当前常用的海洋能利用方式之一。桨叶作为水轮机关键部件,其性能一直是研究的重点。针对目前波浪条件下带负载运转的Savonius型水轮机相关捕能性能研究较少的情况,采用数值仿真方法,结合对应工况条件的物理试验,研究了一种Savonius型水轮机在不同波浪环境下带负载运转的捕能性能。采用Star CCM+仿真软件,建立数值波浪水池,设置环境参数,划分网格调整变量进行水轮机运转的水动力模型数值研究。在造波试验水池中利用推板改变波浪周期与波高,进行水轮机运转的物理试验。采集在不同负载下水轮机桨叶的转速和扭矩数据,计算并分析功率等参数,总结变化趋势,评价捕能效果。研究发现水轮机在1.6 s的波浪周期条件下,桨叶承受1.5 N·m负载时达到最佳捕能效果,其功率为23 W。为实际海域中水轮机桨叶的结构设计研究和相关工程应用提供参考。     

海底边界效应对海流发电水轮机水动力性能影响研究

对30 W海流能水平轴水轮机进行叶片设计,应用FLUENT软件对水轮机的水动力性能进行数值模拟,研究了边界效应对叶片表面压力、流场、湍流强度、获能和轴向力的影响。受海底边界效应影响,海流速度沿深度呈现梯度变化,底层流速较小,中上层流速较大。边界效应导致水轮机的水动力性能呈现周期性变化,降低了水轮机的获能和轴向力。机组布置时,宜选择水流稳定且流速较大的中上层区域。     

基于实密度的卧式浪流轮机水槽实验研究分析

实密度是影响轮机获能特性的关键因素之一。文中以卧式轮机实密度为基变量,以其获能系数为主要考察点,对3种实密度卧式轮机进行水槽实验方案设计和水动力性能研究。实验分别对水流流速、轮机旋转角速度、主轴转矩以及功率进行测量,并对其对主轴的扭矩、轮机的获能系数以及叶片的旋转特性进行定量分析,最终证实了该卧式轮机的单一运行特性。通过绘制基于实密度的轮机转矩—转角曲线、获能系数—尖速比曲线和轮机功率—尖速比曲线,阐明了实密度影响卧式轮机获能水动力性能的规律,即其获能系数和发电功率都随着工况速比呈先增后降趋势。实密度较低轮机因浪流流失而获得能量小,但实密度过高轮机会导致叶片间湍流涌动,加速叶片失速特性而影响轮机获能。这为卧式浪流轮机结构优化提供了可靠依据和借鉴。