Comparison of velocity and temperature fields for two types of spacers in an annular channel

Abstract

The paper deals with measurement of flow field using a modern laser method (PIV) in an annular channel of very small dimension - a fuel cell model. The velocity field was measured in several positions and plains around the spacer. The measurement was extended also to record temperatures by thermocouples soldered into stainless-steel tube wall. The measurement was focused on cooling process of the preheated fuel cell tube model, where the tube was very slowly flooded with water. Main result of the paper is comparison of two spacer's designs with respect to measured velocity and temperature fields. This text deals with a comparison of two spacer designs, the VAR 01 and VAR 02, on fuel rod models. The fuel rod model represents a vertical annular channel where the spacers are installed. The comparison of the spacers focuses on the development and magnitude of velocity profiles in the annular channel. The velocity profile was investigated using the modern laser method of Particle Image Velocimetry, PIV. PIV requires modifications of the fuel rod design to conform the optical principles and properties at the boundary of two environments. The investigation also included the pressure loss at the fuel rod model for individual spacer shapes at given mass flow rates of the liquid running in the annular channel.