某中小型燃气轮机透平静叶冷效试验研究

研究某中小型燃气轮机透平第一级静叶的冷却效果及其影响因素,在叶身中截面布置热电偶获得叶片表面温度场分布,获得不同流量比、温比、落压比、雷诺数等试验状态下冷却效果。结果表明,叶片叶盆侧温度较低,叶背侧温度较高,靠近尾缘附近温度较高,总体冷却效果较好。透平叶片综合冷却效果随流量比增大而增大,达到一定值时变化不明显,随温比降低,随落压比变化不明显,随雷诺数增加而缓慢降低。

涡轮导叶综合冷效试验件设计及验证

为保证新研制的导向叶片在发动机上可靠工作,须先对其进行冷效试验,以验证气膜冷却的气动参数、几何参数对冷却效果及涡轮气动性能的影响。试验件结构设计中根据相似原则,采用单层干烧结构,并采用UG参数化建模和装配、间隙分析减小装配误差和干涉,提高了冷效试验效率。试验件内温度场、压力场较好,具有良好的耐温性、密封性;试验件设计中,配合更换试验件耐热材料,较常规水冷式试验件结构简单,且加工周期缩短一半,造价减少约60%。

涡轮叶片冷效试验专用蜗壳舱研制

本文较为详细地介绍了通用型涡轮叶片冷效试验专用蜗壳舱的研制过程,经调试试验证实,蜗壳舱的各项指标都达到了设计要求。蜗壳舱的研制成功,提高了我国涡轮叶片冷效试验能力,降低了试验成本,缩短了冷效试验周期,试验效益明显提高。

大尺寸低压涡轮导叶冷效试验件优化及验证

针对大尺寸低压涡轮导叶利用现有冷效试验设备扇形试验段内仅能布置3个叶片、叶栅通道流动周期性无法保证的问题,采用CFD方法分析了周期性无法保证的主要原因,为试验件排气测量段导流板引起测试叶片吸力面激波干涉和流动分离。对比研究4种导流板优化方案发现,采用截断导流板的方案可以消除测试叶片激波干涉,改善扇形叶栅通道流动周期性,使叶片表面流动状态接近理论设计。采用气热耦合计算的叶片壁面温度分布与试验结果吻合良好,验证了优化设计的有效性,为类似大尺寸涡轮叶片扇形叶栅及冷效试验件的设计提供了一种优化思路。

高湍流度格栅下游流场试验研究

为满足高湍流度下涡轮扇形叶栅气动与冷效试验的需求,试制了三种被动控制单平面方形格栅并对其进行了试验验证。对格栅下游流场进行了详细的动态测量,并研究了测量位置、格栅尺寸和来流条件等对格栅下游流场湍流度的影响规律。结果表明,grid 3方案格栅能产生10%以上的湍流度,可作为湍流发生装置并满足后续研究要求;格栅几何特征对其下游湍流度影响显著;在试验范围内,来流速度对湍流度近乎无影响。

某型船用燃气轮机涡轮叶片传热特性试验研究

本文对某型大功率船用燃气轮机涡轮气冷叶片进行了传热特性的试验研究,通过采用控制变量的方法进行模化试验,得到了不同工况点下的温比、流量比、燃气雷诺数下的涡轮叶片冷却效果。通过对试验结果的分析处理,进一步得到了涡轮叶片冷却效果随温比、流量比、燃气雷诺数的影响的变化规律呈指数关系式:θ′=0.363 K■K■Re■。试验结果表明,流量比对冷却的效果影响比较大,温比、燃气雷诺数对冷却效果影响较小;在一定温比、流量比情况下,燃气雷诺数的升高将导致冷却效果的提高。本试验建立该叶片的冷却效果试验关系式,为叶片冷却结构的优化和故障分析提供了试验依据。

热电偶敷设工艺与涡轮叶片表面温度测量的关联分析

为评估使用热电偶测量涡轮叶片表面温度数据结果与真实温度的偏差,确保数据准确和有效使用,针对在涡轮叶片综合冷效试验中应用较多的侵入式热电偶敷设测温方式,从工程应用角度出发,提炼出与涡轮叶片表面温度测量准确度有关联的操作工序引入额外热阻、热电偶埋入深度和热电偶埋入间隙等工艺影响因素。通过数值模拟和试验研究,获取了热电偶埋入深度和埋入间隙的影响规律。

Influence of Cooling Systems on the Behaviour of Dairy Cows Housed in Cubicle Barn

The aim of this paper is to collect information about dairy cow＇s behaviour connected to different environmental conditions. During summer 2009 and winter 2010 experimental trials were arranged to verify the behaviour of dairy cows in a farm located in Po Plain （Italy）. The barn was provided with an air-water cooling system, based on the use of fans and sprinklers placed only in the feeding alley. Two different trials were carried out. The first experiment was targeted on verifying the use of the cubicles by the cows in relation to the availability of the cooling system only in feeding area. The second trial aimed at testing the effectiveness of zone cooling systems placed in the front of cubicles. For this purpose three cubicles in the barn were provided with cooling systems, based on the input of high velocity conditioned air streams. The results clearly remark that the behaviour of the animals is greatly influenced by the environmental conditions. With high temperatures the use of the cubicles is deeply reduced and the animals prefer to stay in feeding area, thus benefiting from the cooling effect of water sprinkled by the showers and of the air streams created by the fans. With air temperatures increasing from 21℃ to 33 ℃ the cows reduce the staying in the cubicles, which gets down from 540 to 32% （r2 = 0.2608）. As regards the efficacy of zone cooling system in the cubicles, the results are not particularly encouraging. The cows continue to use the cubicles without changing the behaviour in relation to the presence of conditioned air flow.

Wind?Induced Interference Effect Between Newly?Built Cooling Tower and Existing Cooling Tower

Disturbance effect is one of the important factors for wind damage to large cooling towers.Existing studies on the wind-induced interference of cooling tower groups are aimed at the same size and the lack of wind-induced interference effects between cooling towers of different sizes.With the background of the additional cooling tower project at Shandong Luxi Power Plant in China,the rigid body pressure wind tunnel test is carried out to obtain 194 conditions for the three combinations of the existing four-tower combination(small size),the new two-tower combination(large size)and the six-tower combination surface wind pressure distribution.Numerical simulation of the surrounding flow field of the cooling tower group with the most unfavorable interference condition of the six-tower combination is conducted using the computational fluid dynamics(CFD)method.Based on this,the characteristics of the average and pulsating wind pressure distribution of the cooling tower surface under the six-tower combination are mainly studied,and the load interference coefficients of the large-sized cooling tower and the small-sized cooling tower under the three tower group combinations are compared.The velocity flow field and vorticity changes around the cooling tower group at unfavorable wind angles are analyzed,and the wind-induced interference mechanism between cooling tower groups of different sizes is mainly refined.Research shows that the interference effect between such cooling tower groups of different sizes is much larger than that of cooling tower groups of the same size,which is specifically manifested as the enhancement effect of small-sized cooling towers and the shielding effect of large-sized cooling towers.The interference coefficient of large-sized cooling tower groups increases by 28%,and the interference coefficient of small-sized cooling tower groups decreases by 6.4%.The airflow acceleration caused by the pinch effect between small-sized cooling tower groups has an adverse effect on large-sized cooling towers and can significantly increase the magnitude of local wind load.The shielding effect of large-sized cooling towers can reduce the overall wind load of small-sized cooling towers.The research conclusions can provide the basis of wind load value design for wind resistance design of such large cooling tower addition projects.