![Sample our Engineering & Technology journals, sign in here to start your access, latest two full volumes FREE to you for 14 days]({"type":"image" , "src" : "/sda/5933/TOC-Subject-Sample-2021-Engineering-Tech.jpg"})
ABSTRACT
A code PNCMC (Program for Natural Circulation under Motion Conditions) has been developed for natural circulation simulation of marine reactors. The code is based on one-dimensional two-fluid model in noninertial frame of reference. The body force term in the momentum equation is considered as a time dependent function, which consists of gravity and inertial force induced by three-dimensional ship motion. Staggered mesh, finite volume method, semi-implicit first order upwind scheme and Successive Over Relaxation (SOR) method are used to discretize and solve two-phase mass, momentum and energy equations. Single-phase natural circulation experiments under rolling condition performed in Institute of nuclear and new energy technology of Tsinghua University and two-phase natural circulation experiments under rolling condition performed by Tan and colleagues are used to validate PNCMC. The validation results indicate that PNCMC is capable to investigate the single-phase and two-phase natural circulation under rolling motion.
Disclosure statement
No potential conflict of interest was reported by the authors.
| Nomenclature | ||
| A | = | Area of cross section (m2) |
| a0 | = | Acceleration of noninertial frame relative to stationary frame (m/s2) |
| Cp | = | Specific heat at constant pressure (J/kg · K) |
| FI | = | Interphase drag coefficients (liquid, vapor) (s−1) |
| FWF, FWG | = | Wall drag coefficients (liquid, vapor) (s−1) |
| fine | = | Extra acceleration (m/s2) |
| g | = | Gravity acceleration (−9.8 m/s2) |
| Hif | = | Volumetric heat transfer coefficient from interface to liquid (W/K · m3) |
| Hig | = | Volumetric heat transfer coefficient from interface to gas (W/K · m3) |
| HLoss | = | Pressure drop (Pa) |
| h | = | Enthalpy (J/kg) |
| Hwf | = | volumetric wall heat transfer coefficient for liquid (W/Km3) |
| Hwg | = | volumetric wall heat transfer coefficient for gas (W/Km3) |
| Mdg | = | Total interfacial force (N) |
| m | = | Mass (kg) |
| P | = | Pressure (Pa) |
| pw | = | Channel perimeter (m) |
| q | = | Heating power (w) |
| q''' | = | Power source (w/m3) |
| r | = | Radial vector of fluid particle in noninertial frame (m) |
| T | = | Temperature (K) |
| t | = | Time (s) |
| U | = | Specific internal energy (J/kg) |
| V | = | Velocity in noninertial frame (m/s), volume (m3) |
| x, y, z | = | Spatial coordinate (m) |
| Greek letters | = |
|
| α | = | Gas volume fraction |
| αgw | = | Gas volume fraction near wall |
| αfw | = | liquid volume fraction near wall |
| ζh | = | heating perimeter (m) |
| ρ | = | Density (kg/m3) |
| Γwg | = | Volumetric mass exchange rate near wall (kg/m3 · s) |
| φ | = | Rolling angle (rad) |
| ω | = | Angle velocity of noninertial frame (rad/s) |
| τ | = | Shear stresses (N), rolling period (s) |
| = | Angle acceleration of noninertial frame (rad/s2) | |
| ϖd | = | Rolling frequency of noninertial frame (Hz) |
| Subscripts | = |
|
| f | = | Liquid phase |
| g | = | Gas phase |
| j | = | Spatial noding indices for junctions |
| K | = | Spatial noding index for volumes |
| L | = | Spatial noding index for volumes |
| k | = | k = f or k = g |
| m | = | Maximum |
| i | = | Two-phase interface |
| s | = | Saturation state, heat structure |
| sf | = | Saturation state of liquid |
| sg | = | Saturation state of gas |
| w | = | Pipe wall |
| z | = | Main stream |
| Superscripts | = |
|
| n, n + 1 | = | Time level index |
| • | = | Donored quantity |
| * | = | Bulk/saturation property |