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中文摘要：
针对ISO6358标准及其流量扩展表示式在描述多孔质气动元件流量特性上的缺陷,考虑多孔介质内部气孔率和流体基本流动规律,基于Darcy-Forchheimer定律对多孔质气阻元件建立流量特性模型。空气在多孔质内流速较低时,利用Darcy定律表示流速与压力梯度的关系;当流速增大到一定程度时,通过在Darcy定律的基础上增加一个惯性项构成Forchheimer定律来表征流动特性。采用4种不同尺寸,不同气孔率的烧结金属多孔质气阻进行流量特性试验验证。将流量特性分段进行处理,对模型中的渗透系数和惯性系数提出相应的参数辨识方法,即通过对小压差区域的试验数据进行线性拟合来获取渗透系数,而利用雷诺数大于0.1的数据通过高斯——牛顿非线性最小二乘法确定惯性系数。试验结果表明,该模型可以准确表示被测元件的流量特性,计算结果相对试验误差小于2%。同时,试验系统能够保证渗透系数测试误差小于3%,测试精度足以满足绝大多数工业场合的要求。
英文摘要：
In view of the existing problems of ISO6358 standard as well as its expanded expression in representing the flow rate characteristics of porous media,a Darcy-Forchheimer model is established to describe the flow rate characteristics considering the flow pattern in porous media.Darcy regime provides a good approximate relation between the flow velocity and pressure gradient at sufficiently small flow velocity,while Forchheimer regime is suitable for describing the flow pattern by adding an inertia term on the basis of Darcy regime when the flow velocity is considerably large.Four sintered metal porous air-resistances with different dimensions and porosities are used to perform test for examining the flow rate characteristics that are separated into two regions.Permeability coefficient is first obtained by using the data in Darcy region,and then inertia coefficient is determined by a Gauss-Newton nonlinear least square method with the data satisfying that the Reynolds number is greater than 0.1.Results show that the calculated flow rate agrees with the experimental result,with the error less than 2%.The experimental testing system is able to ensure the permeability coefficient to be measured within a 3% uncertainty,which is sufficient for most applications.
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