垂直向上气液两相流中两相斯托拉赫数的研究

试验研究了三角形、T形两种形状4种规格的物体，在垂直上升气液两相流中，发生气液两相涡街时，气液两相斯托拉赫数的变化规律，在测得大量数据的基础上，得出了发生气液两相涡街时，气液两相斯托拉赫数的通用关系式，研究表明，气液两相斯托拉赫数在两相工况下为一变数，其值与来流截面含气率、涡街发生体形状和特征尺寸、来流方向等因素有关，应用此关系式，根据测得的两相涡街频率可将涡街发生体作为测量两相流流量与组分的测量元件。

STUDY OF GAS-LIQUID TWO-PHASE STROUHAL NUMBER IN VERTICALLY UPWARD GASLIQUID TWO-PHASE FLOW

Strouha number is an important characteristic parameter in studying flowpassing a body . But the gas-liquidtwo-phase Strouhal number is one of the rarely studied subject becauseof the complex of gas-liquid two-phase flow. A study on the gas-liquidtwo-phase Strouhal number is not only valuable for preventing theinduced tube vibration of phase change heat exchangers, but alsoimportant for studying and understanding the gas-liquid two-phase vortexstreet. Moreover the study on the gas-liquid two-phase Strouhal numbermay be set up a new way for measuring gas-liquid two-phase flow rate andcomponent using the characteristics of the gas-liquid two-phase vortexstreet. In this paper, author studied the Strouhal numbercharacteristics in experiment, the gas-liquid two-phase flow passing 4bodies with the direction vertically upward in a inner diameter 50 mmtube. On the basis of measuring a lot of dates, as the gas-liquidtwo-phase vortex street taking place the Strouhal number of gas-liquidtwo-phase can be expressed in the equation below: St{ TPSt{ SP =1.00 - a where StTP is gas-liquid two-phase Strouhal number; StSP is single phase fluid Strouhal number; is void fraction; is slope depended on void fraction, body shape, the ratio ofbody size to pipe size and flow direction etc. From equation(a), thegas-liquid two-phase Strouhal number is a variable in the condition ofthis paper. 　　According to the study of this paper, the conclusion can beobtained: (1) The Strouhal number (StTP) of gas-liquidtwo-phase is a variable and can be expressed by equation (a). StTP depends mainly on void fraction and low dependence on water flowrate Q. The relationship between StTP and is approximately a straightline its slope depends on the direction of gas-liquid two-phase flow,the shape and size of vortex emission body etc. (2) If there is a lotof gas (void fraction more then 10%) in gas-liquid two-phase flow, theKarman vortex street is irregular and the formation and emission ofvortex are influenced. Compared to single flow, the steady gas-liquidtwo-phase vortex street is not easy to form. (3) Using equation(a),according to the two-phase vortex street frequency, the vortexstreet emission body can be used as an element for measuring thetwo-phase flow rat or component. 　　Test condition: Test medium---water, air; temperature---room temperature;Pressure---relative pressure 0.00.2 MPa; Waterdischarge---0.026 m3/h; void fraction---0.00.4; test pipediameter---50 mm; Flow regime---thin bubbly flow.