Temperature Measurement of Fluids Flow by Using a Focusing Schlieren Method

In this work, we propose a method to measure planar temperature fields of fluids flow. We used a focusing schlieren technique together with a calibration procedure to fulfill such purpose. The focusing schlieren technique uses an off-axis circular illumination to reduce the depth of focus of the optical system. The calibration procedure is based on the relation of the intensity level of each pixel of a focused schlieren image to the corresponding cutoff grid position measured at the exit focal plane of the schlieren lens.  The method is applied to measure planar temperature fields of the hot air issuing from a 10 mm diameter nozzle of a commercial Hot Air Gun Soldering Station Welding. Our tests are carried out at different temperature values and different planes along the radial position of the nozzle of the Hot Air Gun Soldering Station Welding. The temperature values obtained experimentally are in agreed with those obtained with a thermocouple.

Development of Grid Depression Model for GalaxyCosmo-S

An efficient grid depression reconstruction model on axial assembly power distribution was developed for MHI nuclear design code system GalaxyCosmo-S. The objective of this paper is to present the background, methodology and its application of the new model in GalaxyCosmo-S. In order to consider the grid depression effect to the homogeneous axial power distribution obtained from 3D nodal core calculation, the new model employs the concept of the pin-power reconstruction model widely used in modern core design codes. In the new model, axial heterogeneous assembly power distribution is calculated by synthesizing the grid form function to the axial homogeneous power distribution by nodal calculation. The form function is pre-produced by fitting the local grid depression data processed from the measured axial thimble reaction rate in the grid position. By incorporating the measured data, the form function can reflect the precise grid depression information. According to the present study, it was shown that the form function has a burnup dependency for its depth, and it is prepared for each fuel type and axial grid position. In order to confirm the applicability of the present method to the existing PWRs, the predicted axial power distribution by GalaxyCosmo-S was compared with the measured data by the movable detector (M/D). As a result, the good agreements were confirmed without any specific trends for burnup condition. In addition, the difference of axial power distribution between predicted and measured data was statistically analyzed for multiple plants, cycles and burnup conditions. From the results, it is confirmed that the systematic over- or under-estimations of the power distribution observed in the grid homogenized model are reduced by the grid depression model. So this model is suitable for the 3D power distribution analysis and FQ uncertainty evaluation.

Numerical Simulation and Flow Field Analysis of Suspended Grid Stilling Pool Based on VOF Method

The unsteady flow RNG k ~ ε turbulence model and VOF Method are employed to numerically simulate 3-D flow field of diversion tunnel outlet stilling pool in Xinjiang dina river wuyi reservoir. The computational and experimental water surface elevation, pressure on the bottom and cross-sectional mean velocity of the suspended grid stilling pool are compared in well agreement. Suspended grid is used in stilling pool, the number of vortex and range are increased in the pool, and the size of the vortex is decreased along with the flow increase. The suspended grid position is determined at end of the vortex. In the suspended grid stilling pool water stability, flow regime is good.