Two-phase pressure drop is studied in a transparent cross-corrugated channel for uniform and non-uniform gas–liquid distribution. Both uniform and non-uniform distribution are created by injecting air and water through different numbers of nozzles directly into the channel. The frictional pressure drop clearly indicates the impact of maldistribution.

The single channel is pivot-mounted to allow horizontal, vertical upward and downward flow. Two-phase frictional pressure drop can be directly measured only for horizontal flow, neglecting acceleration pressure drop. In vertical flow, a void fraction model is necessary to deduct gravitational pressure drop from the measured pressure difference.

The two-phase friction factors of all flow directions are compared to the correlation of single-phase flow. In this manner, homogeneous flow is distinguished from slip. Homogenous flow is confirmed for homogeneous void fractions up to 0.7 at uniform and up to 0.25 at non-uniform gas injection. The single-phase correlation is valid for homogeneous flow when inserting two-phase variables. The experimental two-phase multiplier is compared to correlations from literature.

The pressure measurement data are used to determine the actual void fraction. The results are compared to published void fraction models. The homogeneous model fits best for uniform two-phase distribution. For maldistribution, the correlations of Margat et al. (1997) and of Rouhani and Axelsson (1970) predict the experimental void fractions reasonably well, except for very small flow rates. Analysis of experimental results is facilitated by previously published research on flow pattern visualization and modelling in the same test channel. The cross-corrugated geometry generates a swirling motion inducing centrifugal forces often much larger than buoyancy, which thus loses impact on flow pattern, pressure drop and void fraction. The ratio of buoyancy to centrifugal force is expressed by the corrugation Froude number. Slip independent of buoyancy is identified by introducing the hydrostatic correction factor to evaluate friction factors deviating with flow direction.

在透明的交叉波纹通道中研究了两相压降，以确保气液分布均匀和不均匀。通过将空气和水通过不同数量的喷嘴直接注入通道中，可以产生均匀和不均匀的分布。摩擦压降清楚地表明了分布不均的影响。

单个通道可枢轴安装，以允许水平，垂直向上和向下流动。两相摩擦压降仅在水平流动时可以直接测量，而忽略了加速压降。在垂直流中，必须使用空隙分数模型来从测得的压差中减去重力压降。

将所有流向的两相摩擦系数与单相流的相关性进行比较。以这种方式，均质流与滑移区分开。对于均匀的空隙率，在均匀注入时最高为0.7，在非均匀气体注入时最高为0.25的同质流已得到确认。当插入两相变量时，单相相关对均质流有效。将实验的两相乘法器与文献中的相关性进行了比较。

压力测量数据用于确定实际的空隙率。将结果与已发布的空隙率分数模型进行比较。均质模型最适合于均匀的两相分布。对于分布不均，Margat等人的相关性。（1997）和Rouhani和Axelsson（1970）预测实验空隙率相当好，除了非常小的流速。先前发表的关于在同一测试通道中进行流动模式可视化和建模的研究有助于对实验结果进行分析。交叉波纹的几何形状会产生涡旋运动，从而引起离心力，该离心力通常比浮力大得多，从而对流型，压降和空隙率失去影响。浮力与离心力之比由波纹弗劳德数表示。