Spelling suggestions: "subject:"supercritical water cooled reactors"" "subject:"supercriticaln water cooled reactors""
1 |
Development of a heat-transfer correlation for supercritical water in supercritical water-cooled reactor applicationsMokry, Sarah 01 December 2009 (has links)
A large set of experimental data, obtained in Russia, was analyzed and a new
heat-transfer correlation for supercritical water was developed. This
experimental dataset was obtained within conditions similar to those for proposed
SuperCritical Water-cooled nuclear Reactor (SCWR) concepts. Thus, this new
correlation, for forced convective heat transfer in the normal heat-transfer regime,
can be used for preliminary heat-transfer calculations in SCWR fuel channels. It
has demonstrated a good fit for Heat Transfer Coefficient (HTC) values (±25%)
and for wall temperature calculations (±15) for the analyzed dataset. This
correlation can be used for supercritical water heat exchangers linked to indirectcycle
concepts and the co-generation of hydrogen, for future comparisons with
other independent datasets, with bundle data, as the reference case, for the
verification of computer codes for SCWR core thermalhydraulics and for the
verification of scaling parameters between water and modeling fluids. / UOIT
|
2 |
Computational Study of Critical Flow Discharge in Supercritical Water Cooled ReactorsChatharaju, Madhuri 10 1900 (has links)
<p>Supercritical Water-cooled Reactor (SCWR) is a Generation-IV nuclear reactor design that operates on a direct energy conversion cycle above the thermodynamic critical point of water (374<sup>0</sup>C and 22.1 MPa), and offers higher thermal efficiency and considerable design simplification. As an essential step in the design of SCWR safety systems, the accident behaviour of the reactor is evaluated to ensure that the safety systems can achieve safe shutdown for all the design basis accidents. Unfortunately, the computational tools and computer codes that are currently employed for safety analysis have little application in the supercritical region, and faces significant challenges in simulating the transitions from subcritical to supercritical conditions.</p> <p>This thesis examines the predictive capabilities of Computational Fluid Dynamics (CFD) code STAR-CCM+ by evaluating critical flow (or choked flow) due to accidental release of coolant from supercritical fluid systems. The biggest challenge of this research is that the current version of STAR-CCM+ does not support supercritical simulations because the steam tables included in the package are only limited to the subcritical subset of the thermodynamic fluid properties.</p> <p>The research was carried out in two stages. In the first stage, the CFD code STAR-CCM+ was customized to simulate supercritical conditions by, (i) Generating updated steam tables to include subcritical and supercritical fluid properties and using more pressure and temperature points in the pseudo critical region (22 – 25 MPa, 645 -660 K) to handle the rapid changes in the fluid properties, and (ii) Implementing a multi-dimensional steam table interpolation scheme to access the fluid property data at any thermodynamic state during the simulation. In the second stage, the customized CFD code was extensively evaluated by simulating several accidental release scenarios from supercritical conditions using rounded-edge and sharp-edge nozzles and the model results were validated with experimental data. To overcome the solution stability (or convergence) issues encountered during the supercritical simulations, a fine tuning procedure was proposed that guaranteed convergence for all the case studies considered in this thesis.</p> <p>The simulation results revealed that the CFD model produced results that were in good agreement with experimental data and only about 10% prediction error was noticed for most cases considered in the thesis. Considering the sensitivity of the CFD model for upstream temperatures and pressures, these results appear to be quite reasonable. From the computational experience gained in this research , we believe that the CFD code STAR-CCM+ is a very useful tool to perform thermal hydraulic simulations for supercritical systems. However, an appropriate customization and extensive validation of the code is required before it can be exclusively used for safety analysis.</p> / Master of Applied Science (MASc)
|
Page generated in 0.1002 seconds