1 Copyright © 2008 by ASME PIV Measurements of Jet Flow Mixing in the Vicinity of Rod Bundles using Matched-Index of Refraction Carlos E. Estrada-Perez Texas A&M University Stephen D. Fortenberry Texas A&M University Yassin A. Hassan Texas A&M University ABSTRACT In this study, the velocity field of impinging jets within a rod bundle was developed. Velocity measurements were accomplished using Particle Image Velocimetry (PIV). Additionally, Matched-Index of Refraction (MIR) techniques were implemented to allow the visualization of flow characteristics within interior areas of the rod bundle which would typically be obstructed. Such measurements are of importance and essential to the development of new models to predict the systems’ hydraulic behavior. INTRODUCTION The development of advanced, environmental- friendly energy sources is essential to ensure the sustainability of society’s developed infrastructure. Thus, the proposed development of the Next Generation Nuclear Plant (NGNP), which seeks to develop more efficient nuclear power production systems, may be integral to securing nuclear energy’s place as an important energy source. Therefore, properly characterizing physical phenomena controlling the behavior of the NGNP and developing new models which allow accurate predictions of the hydraulic behavior of these systems is of great importance. One reactor design under consideration by the NGNP program is Advanced Gas Cooled Reactor (AGCR). This investigation, contributes to efforts to properly characterizing these systems by providing experimental observations of phenomena controlling the flow behavior in the lower plenum of an AGCR. Different phenomena occurring in the lower plenum flows such as flow mixing and the velocity fields within the rod bundles and the jet impingement have been studied experimentally to enhance the existing models and to develop new models predicting the flow structure within the rod bundles. Cooper et al (1993) studied the case of a turbulent jet with different heights and flowrates impinging orthogonally upon a large plane surface and obtained the mean velocity profile near the plate surface. Sakakibara et al (1997) measured the velocity and temperature in the stagnation region of an impinging jet using Particle Image Velocimetry (PIV) and Laser Induced Fluorescence (LIF) methods. McEligot and McCreery (2004) emphasized the importance of thorough investigations of the flow characteristics in the lower plenum of an AGCR under different operating conditions; including the extreme conditions such as Loss of Coolant Accident (LOCA).Abdel- Fattah (2007) studied the effects of two circular impinging jets without any crossflow with different Reynolds numbers. This study determined that changing the distance between the two jets, the jet angle and the nozzle to plate spacing affected the flow characteristics. In this study, as an extension of the investigations of Dominguez-Ontiveros et al (2007), PIV and MIR techniques were used to obtain the full-field velocity profiles of two circular impinging jets within a rod bundle. This data may aid in the calculation of certain flow parameters which would be of importance in modeling the fluid flow behavior in an AGCR. METHODOLOGY The system, presented in Figure 1, was used in the conduction of experiments to model the flow behavior in the lower plenum of an AGCR. To allow flow visualization within the rod bundles, the MIR techniques were implemented. Noushin Amini Texas A&M University Elvis E. Dominguez-Ontiveros Texas A&M University Proceedings of the 16th International Conference on Nuclear Engineering ICONE16 May 11-15, 2008, Orlando, Florida, USA ICONE16-48853 Downloaded From: http://proceedings.asmedigitalcollection.asme.org/ on 04/30/2014 Terms of Use: http://asme.org/terms