Preliminary characterization of an expanding flow of siloxane vapor MDM

1st International Seminar on Non-Ideal Compressible-Fluid Dynamics for Propulsion & Power

物理学;力学

Spinelli, A.^1 ; Cozzi, F.^1 ; Cammi, G.^1 ; Zocca, M.^2 ; Gaetani, P.^1 ; Dossena, V.^1 ; Guardone, A.^1

Department of Energy, Politecnico di Milano, Via Lambruschini 4, Milan

20156, Italy^1

Department of Aerospace Science and Technology, Politecnico di Milano, Via La Masa 34, Milan

20156, Italy^2

关键词: Compressible fluid dynamics;    Converging-diverging nozzles;    Density gradient field;    Laser Doppler Velocimetry;    Organic Rankine Cycle(ORC);    Pressure and temperature;    Quasi-one-dimensional theory;    Schlieren visualization;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/821/1/012022/pdf
DOI  :  10.1088/1742-6596/821/1/012022

学科分类：力学，机械学

来源: IOP

【 摘 要 】

The early experimental results on the characterization of expanding flows of siloxane vapor MDM (C8H24O2Si3, octamethyltrisiloxane) are presented. The measurements were performed on the Test Rig for Organic VApors (TROVA) at the CREA Laboratory of Politecnico di Milano. The TROVA test-rig was built in order to investigate the non-ideal compressible-fluid behavior of typical expanding flows occurring within organic Rankine cycles (ORC) turbine passages. The test rig implements a batch Rankine cycle where a planar converging-diverging nozzle replaces the turbine and represents a test section. Investigations related to both fields of non-ideal compressible-fluid dynamics fundamentals and turbomachinery are allowed. The nozzle can be operated with different working fluids and operating conditions aiming at measuring independently the pressure, the temperature and the velocity field and thus providing data to verify the thermo-fluid dynamic models adopted to predict the behavior of these flows. The limiting values of pressure and temperature are 50 bar and 400 °C respectively. The early measurements are performed along the nozzle axis, where an isentropic process is expected to occur. In particular, the results reported here refer to the nozzle operated in adapted conditions using the siloxane vapor MDM as working fluid in thermodynamic regions where mild to medium non-ideal compressible-fluid effects are present. Both total temperature and total pressure of the nozzle are measured upstream of the test section, while static pressure are measured along the nozzle axis. Schlieren visualizations are also carried out in order to complement the pressure measurement with information about the 2D density gradient field. The Laser Doppler Velocimetry technique is planned to be used in the future for velocity measurements. The measured flow field has also been interpreted by resorting to the quasi-one-dimensional theory and two dimensional CFD viscous calculation. In both cases state-of-the-art thermodynamic models were applied.