Abstract A novel design of a pulse expansion wave tube (PEWT) for the study of homogeneous nucleation in mixtures of vapours and gases is presented. The main difference with the previous design consists in a test section with flat walls, which avoid that optical windows and pressure transducers do affect the flow field locally. Additionally, the test section length is reduced by a factor two. The performance of the wave tube is investigated both experimentally and numerically. The thermal insulation of the piezoelectric pressure sensor is proved to be beneficial for accurate measurements. The smallest thickness possible of the diaphragm, initially separating the high- and low-pressure sections of the PEWT, is also shown to be crucial. The flow phenomena are simulated with a 2D numerical model. It is shown to correctly predict the gasdynamic features of the PEWT and the effects of the diaphragm opening process. Nucleation rates for water in helium are determined as a function of supersaturation for two different pressure conditions, 1 MPa and 0.1 MPa, at a temperature of 240 K. The good agreement with results from previous experiments shows that the geometrical mismatch of optical windows and pressure transducers in the original wave tube did not affect the nucleation rates significantly and that both the original and the new wave tube produce reliable measurement data. Graphic abstract

中文翻译：

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脉冲膨胀波管均匀成核研究的新型测试部分：实验验证和气体动力学二维数值模型

摘要 提出了一种用于研究蒸汽和气体混合物中均匀成核的脉冲膨胀波管 (PEWT) 的新设计。与之前设计的主要区别在于测试部分具有平坦的壁，可避免光学窗口和压力传感器确实影响局部流场。此外，测试段长度减少了两倍。对波管的性能进行了实验和数值研究。压电压力传感器的热绝缘被证明有利于精确测量。隔膜的尽可能小厚度，最初将 PEWT 的高压和低压部分分开，也被证明是至关重要的。流动现象是用二维数值模型模拟的。它被证明可以正确预测 PEWT 的气体动力学特征和隔膜打开过程的影响。在 240 K 的温度下，氦气中水的成核率被确定为过饱和度的函数，1 MPa 和 0.1 MPa，温度为 240 K。与先前实验结果的良好一致性表明光学窗口和压力的几何不匹配原始波管中的换能器不会显着影响成核率，并且原始波管和新波管都能产生可靠的测量数据。图形摘要 与先前实验结果的良好一致性表明，原始波管中光学窗口和压力传感器的几何失配并未显着影响成核速率，并且原始波管和新波管均产生可靠的测量数据。图形摘要 与先前实验结果的良好一致性表明，原始波管中光学窗口和压力传感器的几何失配并未显着影响成核速率，并且原始波管和新波管均产生可靠的测量数据。图形摘要