一种轮组式爬楼梯轮椅轮系的结构设计

我国有着庞大的人口基数,同时残疾人士的数量也是非常之大。老年人士以及残疾人士出行不变的问题迫切的需要解决,所以具有一定越障能力的轮椅也就应运而生。本次设计首先分析了应该要满足的性能指标,根据国家标准及设计要求对轮组式爬楼梯轮椅的轮系进行了设计选择,通过分析选择了四星轮式行星轮结构,并对照进行了星轮臂架的设计、电机的选型以及内部传动部分的选择等。在最后通过软件仿真对星轮臂架以及一级锥齿轮传动轴进行了强度校核,校核结果满足本次设计的要求,最终设计出了一种轮组式爬楼梯轮椅的轮系,具有安全稳定载重能力强等多重特点,为爬楼梯轮椅轮系的设计多了一种参考选择。

助力爬楼装置分析研究

对腿足式、轮组式、履带式和复合式四大类助力爬楼装置从结构、运动方式、体积、安全性和功能等方面进行详细的对比与分析,重点分析了各类助力爬楼装置的机械结构与功能。通过分析可知,每种助力爬楼装置都有其利弊:腿足式爬楼装置对楼梯适应性强,但稳定性差;轮组式爬楼装置稳定性好,但体积较大;履带式爬楼装置运动平稳,但结构笨重,对楼梯损害程度大;复合式爬楼装置将2种或2种以上的原始爬楼装置结合为一体,进行了有效的扬长避短,实现了运动过程的优化,但仍有改进空间。通过对各种助力爬楼装置的比较发现,研发一款综合性能好、能解决上述问题、保证老年人安全的创新型爬楼装置,帮助行动不便的老年人解决爬楼问题,具有较为广阔的市场前景。

滑轮组合式悬吊牵引架辅助复位经皮椎弓根钉内固定治疗胸腰段脊柱骨折

目的探讨滑轮组合式悬吊牵引架辅助复位经皮椎弓根钉内固定治疗胸腰段脊柱骨折的临床效果。方法回顾性分析自2016-02—2018-12采用经皮椎弓根钉内固定治疗的55例胸腰段脊柱骨折,28例术前采用滑轮组合式悬吊牵引架复位骨折(观察组),27例采用垫枕联合腰背伸功能训练复位(对照组)。比较2组手术时间、术中出血量、住院时间、末次随访时伤椎Cobb角及疗效。结果 55例均获得随访,随访时间为18个月。观察组1例出现伤口感染,对照组1例出现伤口感染、1例出现褥疮,经对症治疗后症状均改善。观察组手术时间较对照组短,术中出血量较对照组少,住院时间较对照组短,末次随访时伤椎Cobb角较对照组小,疗效较对照组优,差异有统计学意义(P <0.05)。结论经皮椎弓根钉内固定治疗无神经损伤的胸腰段脊柱骨折具有创伤小、术后恢复快等优点,术前采用滑轮组合式悬吊牵引架进行骨折椎体复位符合微创理念,可进一步缩短手术时间,改善后凸畸形,促进骨折愈合与脊柱功能恢复。

On-Cam Operation of Counter-Rotating Type Hydroelectric Unit

The counter-rotating type hydroelectric unit, which is composed of the axial flow type tandem runners and the peculiar generator with double rotational armatures, has been proposed. In the unit, the front and the rear runners counter-drive the inner and the outer armatures of the generator, respectively. Besides, the flow direction at the rear runner outlet must coincide with the direction at the front runner inlet, because the angular momentum change through the rear runner must coincides with that through the front runner. In this paper, the tandem runners work at on-cam conditions in keeping the induced frequency constant, to provide the hydroelectric unit for the power grid system. The output and the hydraulic efficiency are affected by the adjusting angles of the front and the rear blades. Both optimum angles giving the maximum output or efficiency were presented at the various discharge/head circumstances, accompanying with the turbine performances.

Counter-Rotating Type Pump-Turbine Unit Stabilizing Momentarily Fluctuating Power from Renewable Energy Resources

It is difficult for renewable energy resources to provide constant power with excellent quality for the grid system. This serial research proposes a power stabilization system with a pumped storage to guarantee power quality and capacity, while the outputs from the energy resources are at unstable and/or fluctuating conditions. The power stabilization system with a counter-rotating type pump-turbine unit was prepared and operated at the pumping and the turbine modes. The unit composed of the tandem impellers/runners connected to the inner and the outer armatures of the unique motor/generator. The experiments have verified that this type pump-turbine unit is reasonably effective to stabilize momentarily/instantaneously the fluctuating power from the renewable energy resources.

Performance Analysis of the Aeration Valves and Its Protections at the Generating Units in ITAIPU Hydroelectric Power Plant

With the growing energetic need present in the world, it is increasingly necessary for the researches and facilities to seek a better use of renewable natural resources. This paper is applied in the study of the performance of the aeration system of the Francis turbines present in Itaipu Hydroelectric Power Plant. When a Francis turbine operates off its optimal conditions, a vortex is formed inside the draft tube that, besides produces cavitation and pressure fluctuations, can pulse at frequencies with risk of resonance with hydraulic system, producing efforts and vibrations that may cause structural failures in the turbines, generators and civil parts of the power house. These damaging effects can be reduced using atmospheric aeration of the turbines. Because of this, the availability and effectively of the aeration system is fundamental to smooth the behavior of the turbines, helping preserve the health of the power plant. An analysis of the performance of the aeration system will be done using maintenance records and disturbances analysis reports （RAP）, allowing verification of the operating conditions of the turbine and fatality of water inlet in air pipes. Through the improvements detected, it is possible to reduce machine stoppages by tripping, thus increasing the availability of the turbines.

Global Evaluation of Energy in Hybrid M-HTFC/MGT Systems in Cogenerative Arrangement

This work concerns the study of HSs （Hybrid Systems） that are made up of the integration of M-HTFC （Medium and High Temperature Fuel Cell） and MGT （Micro-Gas-Turbine）. Different typologies of hybrid systems are taken into account, which differ from each other in their plant layouts. The plants are considered in cogenerative arrangement. The aim of this study is to carry out an energetic analysis of the HS considered to obtain an analytical expression to depict the system operating in cogenerative arrangement. An energetic comparison among the systems analyzed based on some indexes is effected, which allows an evaluation of the plants performances in cogenerative arrangement. An energetic analysis is carried out, which is based on a ＂black box＂ depiction of the plant in which the components and the mutual interactions are highlighted. The fuel cell component of the plant is not analyzed as a black box, but each element that constitutes it, is elaborated as a subsystem.

Turbine efficiency test on a large hydraulic turbine unit

The flow rate measurements are the most difficult part of efficiency tests on prototype hydraulic turbines.Among the numerous flow rate measurement methods,the Winter Kennedy method is preferred for measuring turbine flow rates,since it is convenient,practical and economical.This paper describes efficiency tests on a large 300 MW Francis turbine,with the flow rate measured using the Winter Kennedy method and the Winter Kennedy flow rate coefficient calibrated using the Gibson method.The measured turbine efficiency curve is then compared with the curve provided by the manufacturer.The CFD calculations including the spiral case are then used to analyze the influence with the coefficient K and index n in the Winter Kennedy flow rate formula on the flow rate measurement.The uncertainty values of n and K are a key reason for the differences between the curves obtained from the efficiency test and the curves provided by the manufacturer.

Counter-Rotating Type Pump-Turbine Unit Cooperating with Wind Power Unit

This serial research proposes the hybrid power system combined the wind power unit with the counter-rotating type pump-turbine unit,to provide the constant output for the grid system,even at the suddenly fluctuating/turbulent wind.In this paper,the tandem impellers of the counter-rotating type pumping unit was operated at the turbine mode,and the performances and the flow conditions were investigated numerically and experimentally.The 3-D turbulent flows in the runners were simulated at the steady state condition by using the commercial CFD code of ANSYS-CFX ver.12 with the SST turbulence model.While providing the pump unit for the turbine mode,the maximum hydraulic efficiency is close to one of the counter-rotating type hydroelectric unit designed exclu-sively for the turbine mode.Besides,the runner/impeller of the unit works evidently so as to coincide the angularmomentum change through the front runners/impellers with that through the rear runners/impellers,namely to take the axial flow at not only the inlet but also the outlet without the guide vanes.These results show that this type of unit is effective to work at not only the pumping but also the turbine modes.