【作者】 张占峰；

【导师】 汤荣铭；

【作者基本信息】 清华大学 ， 力学， 2004， 硕士

【摘要】 流量计量是计量科学的重要组成部分之一,它与工农业生产、国防建设、科学研究以及人民生活有密切关系。做好流量计的研究和开发工作,对于保证产品质量、提高生产效率、促进科学技术的发展都具有重要的意义。特别是在能源危机、工业生产自动化程度越来越高的当今时代,流量计在国民经济中的地位与作用更加明显。本课题第一部分的任务是设计一种差压式流量计的差压发生器。虽然目前市场上的流量计种类繁多,但都有不同的缺点,已经不能完全满足现今科研和工农业生产的需要。差压流量计的特点是结构简单,造价低,但多数的差压流量计造成的压损较大,某些还极易造成测压孔的堵塞,使其使用寿命减少。为了获得高精度,较低压损,重复性好的差压式流量计,本论文进行如下的探讨工作:一、根据伯努利方程,设计一种新型差压发生器。它呈流线型结构,解决堵塞了问题和断裂问题等,可标准化生产。它可以达到高重复度、高精确度。二、把测压孔选在管道速度剖面的不同位置处,做相关的实验研究,从而确定最终的取压孔位置。本课题第二部分的任务是开发一种新型流量计。它要能够测量旋转管道内的流体,具有大量程,不受上游配管影响等特点。这一部分任务的重点是针对这种新型流量计的旋流器,采用三种测速方法(激光、热线、五孔探针),做速度和压强方面的实验。然后再对旋流器进行数值模拟,分析对比四种方法结果,从而更为清楚的了解到旋流器内流场的特征,为新型流量计的设计提供可靠的依据。为此,论文进行了如下工作:一、分别采用五孔探针、热线和激光三种流场测量方法测量旋流器模型内的速度场和压强场。在旋流器内,三维的运动以切向速度为主,所以主要测量切向速度。轴向速度关系到回流,所以也尽可能得去测。径向速度最小,也最难以测量。为了下一步设计流量计和无接触吸盘的需要,压强场也很关键,压强包括分为总压和静压。二、使用FLUENT大型计算软件,对流量计的旋流器流场进行数值模拟。如<WP=4>果实验跟计算吻合,则增强数据的可靠性。三、设计出这种新型流量计。更多还原

【Abstract】 Flowmeter is an important part of measurement science, and has been widely applied in production of industry and agriculture, national defence construction, scientific research work and civil economy. The research and development of flowmeter will be propitious to develop the product quality, improve efficiency of production and expedite the development of science and technology. Especially in the near future, we will face the crisis of energy, and the extent of automatization in industrial production will also get more and more. All these will make the status of flowmeter higher and higher in civil economy.In this thesis, the first part is to design a differential pressure(DP) flowmeter. Although there are many kinds of flowmeters on the market, they all have some deficiency and can not fully satisfy the requirement of science research and industrial application. The characteristic of DP flowmeter is cheap and simple structurally. But most of DP flowmeters bring large pressure loss, which can lead to jam and reduce their life. In order to find the higher precision, lower pressure loss and better repetition DP flowmeter, the groping work is included as follows:1. Designing a new kind of differential generator based on bernoulli equation. It has streamline structure, solve the problems of jamming and parting, and can be standardizationally produced. Besides, it can have high repetition and precision.2. Doing the experiment through different load orifice on the different position of velocity section in the pipeline. So the position of the best load orifice can be made certain.The second part is to invent a new flowmter. It must be able to measure the flux of vortical liquid in the pipeline with the large metrical range, but not be affected by upriver tubing. The emphasis of this part is to get velocity field and pressure field of vortical liquid with the experiment methods of LDV, hotwire and five-hole probe. The numerical simulation is also gotten. By the contrast of results with four deferent methods, the character of the swirler field can be known. In this part the flowing works are included: <WP=6>1. Measuring the field of velocity and pressure in swirler by five-hole probe, hotwire and LDA. The tangent velocity is the main one of the three-dimensional velocity in the swirler, so it must be mainly measured. The axial velocity is related to backflow, so it can be measured as possible. The radial velocity is the least one, so it is very difficult to measure. To further design the flowmeter and the noncontact cupule, the pressure field, including static pressure and total pressure, is also very important.2. Simulating numerically the flow field of swirler of flowmeter with Fluent so as to enhance the reliability of experimental data.3. Designing the new kind of flowmeter on the whole.更多还原