The accidental releases of pressurized liquefied gases from tanks involve violent phase transformation, which would generate two-phase releases and flashing jets. To investigate the evolution of leakage behaviors and make an analysis of near-field jet flow characteristics, a small-scale liquefied gas release experiment has been established. Leakage holes with different length-diameter ratio (LDR) have been used to analyze interactions between the leakage holes and release behaviors. Morphological characteristics of jet expansion angles have been obtained by high-speed camera, and jet velocities have been measured by particle image velocimetry (PIV). Meanwhile, the depressurization process, variation of temperature in the tank and mass outflow rates were obtained. Results show that, despite the LDR is varying, expansion angles and jet velocities behavior in the same tendency: decreases in the initial and maintains in a stable value for a period. The stable velocity status was worked by the balanced pressure drop. Thereafter, an empirical two-phase mass outflow rate model is developed based on the experimental data, which is related to the nozzle geometric parameter and upstream pressure, 90 % of the experimental data are within ±12 % of the prediction. Therefore, the empirical two-phase model can be supported in the mass flow rate evaluation, especially for the release cases that LDR are smaller than 5.00 but larger than 2.00. The experimental data is beneficial for providing further insight into the prediction of accidental release and risk assessment for the liquefied gas transportation and storage.

储罐中加压液化气体的意外释放涉及剧烈的相变，这将产生两相释放和急速喷射。为了研究泄漏行为的演变并分析近场射流特性，建立了小型液化气释放实验。具有不同长径比（LDR）的泄漏孔已用于分析泄漏孔与释放行为之间的相互作用。射流膨胀角的形态学特征已经通过高速照相机获得，并且射流速度已经通过粒子图像测速法（PIV）测量。同时，获得了减压过程，罐中温度的变化和质量流出速率。结果表明，尽管LDR有所不同，膨胀角和射流速度行为具有相同趋势：初始时减小，并在一段时间内保持稳定值。稳定的速度状态通过平衡的压降工作。此后，根据实验数据建立了经验的两相质量流出率模型，该模型与喷嘴的几何参数和上游压力有关，实验数据的90％在预测值的±12％之内。因此，经验两相模型可以在质量流率评估中得到支持，特别是对于LDR小于5.00但大于2.00的释放情况。实验数据有助于进一步了解液化气运输和储存的意外释放预测和风险评估。减少初始值，并在一段时间内保持稳定值。稳定的速度状态通过平衡的压降工作。此后，根据实验数据建立了经验的两相质量流出率模型，该模型与喷嘴的几何参数和上游压力有关，实验数据的90％在预测值的±12％之内。因此，经验两相模型可以在质量流率评估中得到支持，特别是对于LDR小于5.00但大于2.00的释放情况。实验数据有助于进一步了解液化气运输和储存的意外释放预测和风险评估。减少初始值，并在一段时间内保持稳定值。稳定的速度状态通过平衡的压降工作。此后，根据实验数据建立了经验的两相质量流出率模型，该模型与喷嘴的几何参数和上游压力有关，实验数据的90％在预测值的±12％之内。因此，经验两相模型可以在质量流率评估中得到支持，特别是对于LDR小于5.00但大于2.00的释放情况。实验数据有助于进一步了解液化气运输和储存的意外释放预测和风险评估。此后，根据实验数据建立了经验的两相质量流出率模型，该模型与喷嘴的几何参数和上游压力有关，实验数据的90％在预测值的±12％之内。因此，经验两相模型可以在质量流率评估中得到支持，特别是对于LDR小于5.00但大于2.00的释放情况。实验数据有助于进一步了解液化气运输和储存的意外释放预测和风险评估。此后，根据实验数据建立了经验的两相质量流出率模型，该模型与喷嘴的几何参数和上游压力有关，实验数据的90％在预测值的±12％之内。因此，经验两相模型可以在质量流率评估中得到支持，特别是对于LDR小于5.00但大于2.00的释放情况。实验数据有助于进一步了解液化气运输和储存的意外释放预测和风险评估。质量流率评估可以支持经验两相模型，特别是对于LDR小于5.00但大于2.00的释放情况。实验数据有助于进一步了解液化气运输和储存的意外释放预测和风险评估。质量流率评估可以支持经验两相模型，特别是对于LDR小于5.00但大于2.00的释放情况。实验数据有助于进一步了解液化气运输和储存的意外释放预测和风险评估。