Nuclear Engineering and Design 241 (2011) 4165–4180 Contents lists available at ScienceDirect Nuclear Engineering and Design j ourna l ho me page: www.elsevier.com/locate/nucengdes Flow distribution in the inlet plenum of steam generator H.P. Khadamakar a , A.W. Patwardhan a,∗ , G. Padmakumar b , G. Vaidyanathan b a Department of Chemical Engineering, Institute of Chemical Technology, Matunga, Mumbai 400 019, India b Experimental Thermal Hydraulics Section, Separation Technology and Hydraulics Division, Fast Reactor Technology Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, India a r t i c l e i n f o Article history: Received 19 July 2010 Received in revised form 20 July 2011 Accepted 25 July 2011 a b s t r a c t The flow distribution in a 1/5th and 1/8th scale models of inlet plenum of steam generator (SG) has been studied by a combination of experiments and Computational Fluid Dynamics (CFD) simulations. The distribution of liquid sodium in the inlet plenum of the SG strongly affects the thermal as well as mechanical performance of the steam generator. Various flow distribution devices have been used to make the flow distribution uniform in axial as well as tangential direction in the window region. Experiments have been conducted to measure the radial velocity distribution using Ultrasonic Velocity Profiler (UVP) and Particle Image Velocimetry (PIV) under a variety of conditions. CFD modeling has been carried out for various configurations to give more insight into the flow distribution phenomena. The various flow distribution devices have been compared on the basis of a non-uniformity index parameter. © 2011 Elsevier B.V. All rights reserved. 1. Introduction Fast Breeder Reactor (FBR) is liquid sodium cooled pool type reactor. Heat generated in the core is removed by primary sodium circuit. The hot liquid sodium from primary circuit exchanges heat with liquid sodium in secondary sodium circuit. The hot liquid sodium from secondary circuit exchanges heat with water in steam generator to produce superheated steam. The steam generator (SG) is a shell and tube type of heat exchanger. A typical steam gener- ator is shown in Fig. 1. Liquid sodium enters the shell side of SG through the side nozzle. It rises up in the annular space, enters into the window region of the tube bundle and flows downward. Water flows on tube side. The tubes encounter the cross flow of liquid sodium at the inlet window region. The tubes are slim and long and are therefore prone to flow induced vibrations generated by cross flow of sodium in the inlet window region. This is a poten- tial cause of tube rupture. Thus it is essential to characterize the flow distribution in the inlet plenum of SG and to devise strate- gies to make the flow distribution uniform. The cross flow sodium velocity will be minimum if the sodium enters/leaves the tube bun- dle uniformly. Since sodium enters the SG through a single radial nozzle, the flow distribution is far from uniform. It is desirable to make the flow distribution uniform in the window region in axial direction as well as in tangential direction. This can be achieved by using the flow distribution devices in the annular space and in ∗ Corresponding author. Tel.: +91 22 33611111/2018; fax: +91 22 33611020. E-mail address: aw.patwardhan@ictmumbai.edu.in (A.W. Patwardhan). the window region. Effectiveness and suitability of such devices need to be established experimentally. In order to reduce the num- ber of experiments, numerical simulations are required. In the next section, published literature has been critically analyzed to deter- mine shortcomings in the previous work and thereby to decide the objectives for the present work. 2. Previous work Brown and Scriven (1985) have carried out two-dimensional simulations for inlet and outlet regions of steam generator using PHOENICS code. They have found that inlet velocities at the inlet were highly non-uniform in the window region with maximum velocity in the bottom region of the window. The tangential variation in the inlet velocities was not accounted due to two- dimensional simulation geometry. Padmanabhan et al. (1992) investigated the flow distribution at the bottom region of a steam generator tube bundle. Experi- ments were conducted in a 1/3rd scale model and axial velocities were measured at different positions in the window region using laser Doppler velocimetry. Comparison of velocity profiles at dif- ferent tangential positions showed that the velocity field was non-uniform in the tangential direction. Velusamy et al. (1997) have carried out experiments and 3D sim- ulations in the full scale 60 ◦ sector model to determine the velocity fields in the inlet plenum of steam generator. They showed that the top part of the window in basic configuration does not partic- ipate in the flow and flow distribution is non-uniform especially along the window height. They have concluded that uniformity 0029-5493/$ – see front matter © 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.nucengdes.2011.07.041