This paper reports on experiments aiming to understand and to characterize how the working fluid spreads in an organic Rankine cycle (ORC) power system. To this end, a 2-${\mathrm{kW}}_{\mathrm{e}}$ ORC test rig is constructed and tested over a wide range of conditions. Besides standard thermo-hydraulic sensors, the fluid charge distribution is measured on-line by bending load cells and infrared imaging techniques. Following a complete experimental campaign (which includes more than 330 steady-state points and fully characterizes the ORC off-design behaviour), a dual data reconciliation method is applied to the raw measurements to obtain a reference dataset. The results are then analysed to assess the charge distribution mechanisms occurring in the ORC and how it is correlated with the system performance. Among other aspects, this paper demonstrates (i) how the charge inventory is highly correlated to the temperature profiles in the heat exchangers, (ii) how the evaporator dictates the operating conditions of the low-pressure components, and (iii) how the system charge and the liquid receiver size can be selected to maximize the ORC overall performance.

本文报道了旨在理解和表征工作流体如何在有机朗肯循环（ORC）动力系统中扩散的实验。为此，一个2-${\mathrm{千瓦}}_{\mathrm{Ë}}$ORC测试台是在各种条件下建造和测试的。除标准的热液传感器外，还通过弯曲称重传感器和红外成像技术在线测量流体电荷分布。经过一个完整的实验活动（包括330多个稳态点并充分描述了ORC的非设计行为），将双重数据对帐方法应用于原始测量以获得参考数据集。然后分析结果以评估ORC中发生的电荷分配机制，以及它与系统性能的关系。在其他方面，本文展示了（i）装料存量与热交换器中的温度曲线如何高度相关；（ii）蒸发器如何决定低压组件的工作条件；