Logo VKI
linkedin Instagram YouTube

  • VKI Instrumentation Service


  • 1

Cryogenic Flow Measurements

Contact point: Senior Research Engineer Dr. Jean-Baptiste Gouriet

The Environmental and Applied Fluid Dynamics Department of VKI has been working on many programs related to multiphase flows and heat transfer, including cryogenic liquids.

The aim of the Cryogenic team is to accurately characterize, by means of several type of measurement techniques, fundamental phenomena involved in cryogenic systems. Typical applications are related to cryogenic propellants as well as LNG terminals or automotive industries (fuel cell vehicles). Generally, cryogenic fluids are highly sensitive from the thermodynamic equilibrium point of view, so they often experience a very complex thermo-fluid dynamics.

Both quantitate and qualitative measurements techniques in such conditions are extremely challenging, but nowadays of fundamental importance for the correct design of the mentioned systems.

Over the years, the VKI research group has developed and consolidated its expertise in using as best standard probes to be exploited in the precise measurements of challenging cold environments and multiphase fluid dynamic. Indeed, their knowledge of cryogenic flows associated to the capabilities offered by the sensors available in the market, assures the maximised accuracy in the results, the correction of unwanted spurious effects, the most elevate possible repeatability and reliability of the measured quantities.

Additionally, the VKI Cryogenic team is used to develop in-house and thanks to worldwide academic partnerships, particularly innovate instruments and new measurement methods to match the requirements of specific applications. For example, the quantitative detection by not-intrusive techniques of the flow topology or the reconstruction of a forced convective heat-transfer mechanism by multipoint temperature measurements.

Within the VKI-Instrumentation Service, the Cryogenic Team of the EA Department provides its expertise in the following fields:

Cryogenic Pressure Measurements

  • high time-resolved measurements and simultaneous flow visualizations
  • design and construction of customised sensor-mounting modules
  • particular care to temperature effects compensation
  • sensors calibration check at cold temperature when possible
Bubbly flow during a fluid hammer pressure surges, the high-speed video is synchronized to the measured pressure at the impact location
Bubbly flow during a fluid hammer pressure surges, the high-speed video is synchronized to the measured pressure at the impact location
Instrumented flow visualisation module for fluid hammer experiments
Instrumented flow visualisation module for fluid hammer experiments

Cryogenic Temperature Measurements

  • temperature sensors embedded in the wall thickness and in contact with the flow
  • heat-transfer reconstruction by wall temperature measurements
  • particular care to temperature effects compensation
  • sensors calibration check at cold temperature when possible

Cryogenic Mass Flow Rate and Density Measurements

Cryogenic Void Fraction measurements by capacitive methods*

  • high time-resolved measurements and simultaneous flow visualizations
*Academic Collaborations: Waseda University of Tokyo
Temperature, mass flow rate and void fraction evolution during the chilldown. The high-speed video is synchronized to the measured physical quantities
Temperature, mass flow rate and void fraction evolution during the chilldown. The high-speed video is synchronized to the measured physical quantities
Capacitive sensor integration in the VKI CHIEF test section
Capacitive sensor integration in the VKI CHIEF test section

Solid Mass Fraction Measurements by Capacitive Methods

  • high time-resolved measurements and simultaneous flow visualizations

Cryogenic Quantitative and Qualitative Optical Technique

  • Particle Image Velocimetry
  • Free surface tracking and reconstruction
Particle Image Velocimetry test in liquid nitrogen natural convection
Particle Image Velocimetry test in liquid nitrogen natural convection
Free surface detection in liquid nitrogen sloshing
Free surface detection in liquid nitrogen sloshing

Research and Development

Slurry Characterisation with capacitive and optical probes

The use of cryogenic slush, i.e. a cryogenic liquid at its triple point, as fuel for new generation rocket engines may play a significant role for the development of future launchers due to its higher density and higher specific enthalpy compared to the pure liquid state. Being the slush a mixture of solid and liquid phases, the aerospace industries are more and more interested in the development of instruments or methodologies capable to precisely determine the slush density and concentration, to properly design the launcher propulsion systems.

 

This study focuses on the development of two non-intrusive measurement techniques to determine the concentration and density of a well-known slurry through a circular transparent pipe system. Instead of slush Hydrogen, typically used as space propellant, in this preliminary activity, a slurry is selected by respecting hydrodynamic similarity rules. This approach simplify the conditions for the validation of the probes at ambient temperature.

The two techniques are based on the capacitive and the optical properties of the flow. The capacitive probe is designed by means of electric field analysis (EFA). For the optical technique, background lighting is applied with a constant intensity source, and the images are recorded with a high-speed camera. The experiments are conducted on a test bench developed in the framework the ESA TRP program “PREDICT”. The validation process of the techniques is done with an additional Coriolis flow meter implemented on the slurry test bench allowing to measures the slurry density. The density and concentration results obtained from the reference meter, the capacitive probe and the optical technique are compared and discussed for three test cases. The experimental results show that three techniques are in good agreement for low mass fraction concentrations.

A research was the subject of the research master project of Ş. P. Eneren Aksoy in June 2017 and was supervised by Prof. Jeroen van Beeck, Laura Peveroni, Yushi Sakamoto

Capacitive probe section views and example of contribution of different media to the capacitance
Capacitive probe section views and example of contribution of different media to the capacitance

Relevant Publications

Y. Sakamoto et al., Void Fraction Measurement in Cryogenic Flows. Part I: Design and Validation of a Void Fraction Capacitive Sensor. Submitted to Cryogenics in November 2017.

Y. Sakamoto et al., Void Fraction Measurement in Cryogenic Flows. Part II: Void Fraction Capacitive Sensor Performances in Chilldown Experiments. Submitted to Cryogenics in January 2018.

  1. Peveroni et al., Liquid nitrogen chilldown: void fraction measurements and feasibility of extension to liquid methane testing. Submitted to the Space Propulsion Conference 2018, Seville, Spain.
  2. Simonini et al., Experimental characterisation of LN2 sloshing by means of non-intrusive optical techniques. 24th International Congress of Theoretical and Applied Mechanics ICTAM, 2016, Canada.

J-B. Gouriet et al., Multiphase fluid hammer with non-cryogenic and cryogenic fluids. 8th European Symposium on Aerothermodynamics for Space Vehicles 2 - 6 March 2015, Lisbon, Portugal.

J-B. Gouriet et al., Multiphase fluid hammer with cryogenic fluids. On submission process.

Print