Dr. Satoshi Someya
(AIST, National Institute of Advanced Industrial Science and Technology, Japan)
Date: 28 November
Title: Temperature measurement using luminescence
One of directions of flow visualization studies recently trends to simultaneous/combined measurements of scalar values and velocities in the heat and fluid flow, because correlations of them derives valuable suggestions such as the turbulent heat flux.
In the plenary talk, state-of-the-art technique of luminescence-based simultaneous temperature and velocity measurement is introduced. Temperature sensitive particles are used to visualize the temperature of fluids and a temperature sensitive paint is used to measure a surface temperature.
There are two approaches to estimate temperature, i.e., the lifetime method and the two-color ratiometric method. The lifetime-based method is limited by the particle displacement, however, only one camera is used without any optical filters and image conversion. The ratiometric method has several limitations too, however, it is never limited by the velocity and the high time-resolution is easily available. Both approaches are summarized in the presentation.
The lifetime-based method was applied to the temperature and velocity measurement of solid-liquid multiphase flow and the combined measurement of air flow along the heated wall. The temperature and velocity near the boundary layer were measured and results were compared with numerically obtained temperature and velocity. The two-color ratiometric method was applied to measure the high temperature gaseous flow, over 1000K.
Temperature sensitive particles and other luminescent dyes can be painted a solid surface to measure the temperature distribution. A time delay of heat transfer due to the painted layer itself should be considered. A fabrication method of a thin layer of inorganic phosphor and its response time are also introduced in the talk.
Prof. Yongrong Yang
(College of Chemical Engineering, Zhejiang University, China)
Date: 29 November
Title: A study on the particle flow systems from absolute dry to wet enough
From the experience of nature and industrial application, it is well known that the multi-phase flow behavior of particles will show different and unique behaviors from an extremely droughty to the liquid flood environments. In this paper, it is intended to show some new and interesting performances of particle flow through various measurement methods, so as to deepen the understanding of scientific fundamental on multiphase flow. Firstly, the experimental data of tribo-electrification of the same material particles with the same size are obtained by means of an electrostatic measurement. The important effect of particle morphology on bipolar electrification and the separation characteristics of particles with different morphology under electric field are found for the first time. Secondly, the liquid film coating behaviors of the one droplet impacting one particle was captured by high-speed camera, and the phenomenon of liquid film sliding and recoil on the surface of particles was measured. The relationship between liquid film flow pattern and particle temperature, liquid Weber number and droplet composition was studied, and the flow pattern transition of the liquid film on the particle with liquid phase composition was first discovered. Thirdly, the formation process of the solid bridges between two particles was photographed by thermal image analyzer, and the fast growth mode of solid bridge induced by liquid bridge, the intermittent growth mode of solid bridge induced by liquid droplets and the slow continuous growth mode of solid bridge induced by liquid film were discovered for the first time. Among them, the fast growth model is of great significance for exploring the mechanism of particles agglomeration in gas phase polymerization of ethylene. Lastly, the densification process of particle loading is studied by using synchronous high-speed photography and image recognition. Different from the method of external energy input such as tapping and shearing, it is found here that the particles can be spontaneously densified under the flow pattern of the trickle-flow pattern by using the gas-liquid-solid three-phase co-current moving bed. Meanwhile, the three-stage densification mechanism of particle rearrangement that needs to overcome the energy barrier is revealed by on-line measurement of solid content and the average number of the contact of one particle with others in the bed.
Prof. Yoshiyuki Tagawa
(Tokyo University of Agriculture and Technology, Japan)
Date: 30 November
Title: Optical Stress Field Measurement for Fluids/Soft Materials: BOS and photoelastic measurement
Measuring the three-dimensional stress fields in fluids and soft materials is crucial for complex fluid and soft material studies, with implications in industries like plastic molding and medical developments, such as needle-free injection devices and blood vessel rupture predictions. This talk will introduce two advanced measurement techniques: the BOS method (Background Oriented Schlieren) and the photoelastic measurement.
The BOS method visualizes density gradients and quantifies pressure fields more straightforwardly than other techniques. Its validation has been confirmed using laser-induced underwater shockwaves, with results consistent with hydrophone measurements. The discussion will provide insights on optimal BOS measurement practices.
The photoelasticity method, initially for visualizing stresses in materials like glass, now extends to soft materials, aided by high-speed polarization cameras. This method links light polarization with a material's stress field. Our research indicates its efficacy on materials softer than glass, such as gelatin gels. By incorporating a vector tomography approach, the 3D stress field is accurately reconstructed. The talk will conclude with future prospects of these techniques.
Date: 28 November
Prof. Hiromichi Obara (Tokyo Metropolitan University, Japan)
Prof. Chao Tan (Tianjin University, China)
Title: Horizontal Oil-Gas-Water Three-Phase Flow Characterization and Identification with Differential Pressure and Ultrasonic Sensors
Date: 29 November
Prof. Chuanlong Xu (Southeast University, China)
Title: Calibration of multi-camera light field PIV for accurate 3D flow measurement
Prof. Yohsuke Tanaka (Kyoto Institute of Technology, Japan)