叶轮压缩机

The blade shape line optimum design of centrifugal impeller based on genetic algorithms is studied in this thesis.

本论文主要研究了遗传算法在离心压缩机叶轮叶片型线的优化设计。

The numerical results show that:(1) the throughflow wake is considerably influenced by the tip clearance. The low-kinetic-energy fluid accumulated in the shroud/pressure side of the unshrouded impeller, but in the shroud/suction region for 0.0 tip clearance;(2) there possibly exists an optimum size of the tip-clearance which is not the zero tip clearance to make the flow loss minimized.

研究结果表明，(1)NASA低速大尺度离心压缩机半开式叶轮的低速尾迹区在压力面与轮盖的角区，而相应的闭式叶轮的低速尾迹区聚集在轮盖的中心位置；(2)数值实验表明，叶顶间隙并非越小越好，可能存在一个最优间隙，使得叶轮流动损失最小。

In the present study, the experimental and numerical investigation is carried out at an outward volute of circular cross section cooperating with a centrifugal impeller and a vaned diffuser.

本文对一个包含叶轮、有叶扩压器和蜗壳的单级离心压缩机进行了实验和数值研究。

A turbocharger is a dynamic compressor, in which air or gas is compressed by the mechanical action of impellers, vaned rotors which are spun using the kinetic movement of air, imparting velocity and pressure to the flowing medium.

蒸气增压器是一台动态压缩机，在哪空气或气体由叶轮的机械行动压缩，使用空气的运动运动转动的vaned电动子，给予速度和压力到流动的媒介。

The flowfield and performance of a centrifugal compressor was predicted and analysed, which was composed of a Krain's impeller and two types of vaneless diffuser specially: one was constant area vaneless diffuser and the other was the straight-wall. The results show that the efficiency of the straight-wall vaneless diffuser is obviously lower than that of the constant area, and a separate flow occurs nearby the exit of the centrifugal impeller with the straight-wall diffuser. However, the type of vaneless diffuser has little influence on the aerodynamics performance of the centrifugal impeller. Finally, it is suggested that the constant-area vaneless diffuser should be selected as the downstream extended area of the centrifugal impeller during the prediction for the centrifugal impeller.

对Krain叶轮后带等面积与直壁两种形式的无叶扩压器离心压缩机内部流场进行了计算与分析，结果表明：直壁型无叶扩压器离心压缩机的效率低于等面积无叶扩压器离心压缩机的效率；直壁型无叶扩压器使得叶轮出口的流动出现分离；扩压器的形式对离心叶轮的整体气动性能影响并不大；在进行离心叶轮数值研究时，叶轮后的延伸区最好采用等面积无叶扩压器，以尽量减小无叶扩压器所引起的计算误差。

The centrifugal superchargers use the same type of compressor impeller as a turbocharger and the faster they spin the more boost they make and it is not linier.

离心 增压器使用与A相同的压缩机叶轮的类型他们纺他们做的更多的帮助的turbocharger和更迅速的和它不细弱。

But studies have demonstrated that the impellers' efficiency can reach up to more than 90%.

以单机离心压缩机为例，目前我国设计和生产的机器，其整机效率的期望值为83%左右，但研究表明叶轮的效率则可高达90%以上。

The approach of analyzing the strength and vibration of centrifugal impellers with ANSYS is briefly introduced.

设计高强度高可靠的离心叶轮，是摆在离心压缩机研究者们面前的一个重要任务。

For example, the expected aerodynamic efficiency of the single stage compressors that are currently produced in China is about 83%. But studies have demonstrated that the impellers' efficiency can reach up to more than 90%.

以单机离心压缩机为例，目前我国设计和生产的机器，其整机效率的期望值为83%左右，但研究表明叶轮的效率则可高达90%以上。

But as for impellers and diffusers, not much research was carried on volutes and their design is still based on traditional one-dimensional method.

但是相对于叶轮扩压器而言，关于蜗壳的研究比较少，并且蜗壳的设计也停留在传统的一维设计方法上，此设计方法不符合实际流动情况，导致蜗壳内流体参数不均匀性的增强，进而影响叶轮和扩压器内的流动，降低压缩机整体性能。

We have no common name for a mime of Sophron or Xenarchus and a Socratic Conversation; and we should still be without one even if the imitation in the two instances were in trimeters or elegiacs or some other kind of verse--though it is the way with people to tack on 'poet' to the name of a metre, and talk of elegiac-poets and epic-poets, thinking that they call them poets not by reason of the imitative nature of their work, but indiscriminately by reason of the metre they write in.

索夫农 、森那库斯和苏格拉底式的对话采用的模仿没有一个公共的名称；三音步诗、挽歌体或其他类型的诗的模仿也没有——人们把&诗人&这一名词和格律名称结合到一起，称之为挽歌体诗人或者史诗诗人，他们被称为诗人，似乎只是因为遵守格律写作，而非他们作品的模仿本质。

The relationship between communicative competence and grammar teaching should be that of the ends and the means.

交际能力和语法的关系应该是目标与途径的关系。