Defining the structure of a supercritical carbon dioxide (SC-CO₂) jet flow field is a critical component of establishing a theoretical basis for its application. This study investigates the influence of pressure ratio on the wave features of an SC-CO₂ jet flow field using a new numerical simulation model and flow field visualization experiments. To assess the characteristics of the SC-CO₂ flow field and predict the distribution of temperature and pressure, a computational model based on constant pressure specific heat capacity and thermal conductivity of SC-CO₂ was established, and the user-defined function (UDF) feature available in ANSYS Fluent software was used. The results demonstrated that the temperature and pressure of the SC-CO₂ jet flow field could be accurately predicted by the numerical simulation model proposed in this research, and the wave features of the flow field could be visualized by both the numerical simulation contours and the experiments. The wave features, which resulted from different pressure ratios, were found be a function of the structure of the Laval nozzle at a constant inlet pressure. The pressure ratio could be controlled by the nozzle structure and accurately describe the wave features of the SC-CO₂ jet flow field. In this study, an optimal pressure ratio of 1.31 was used and the flow field structure corresponding to the maximum jet impact force could be satisfactorily described by the optimal pressure ratio.

定义超临界二氧化碳（SC-CO ₂）射流场的结构是为其应用建立理论基础的关键组成部分。本研究使用新的数值模拟模型和流场可视化实验研究了压力比对SC-CO ₂射流流场的波动特征的影响。为了评估SC-CO ₂流场的特性并预测温度和压力的分布，基于恒定压力比热容和SC-CO ₂导热系数的计算模型已建立，并使用了ANSYS Fluent软件中提供的用户定义功能（UDF）功能。结果表明，通过本研究提出的数值模拟模型可以准确预测SC-CO ₂射流流场的温度和压力，并且可以通过数值模拟轮廓和流线形可视化流场的波动特征。实验。发现由不同的压力比产生的波动特征是在恒定入口压力下拉瓦尔喷嘴结构的函数。可以通过喷嘴结构控制压力比，并准确描述SC-CO ₂的波动特征射流场。在这项研究中，使用的最佳压力比为1.31，并且通过最佳压力比可以令人满意地描述与最大射流冲击力相对应的流场结构。