Dynamic analysis of heated channels with time-dependent inlet temperature, heat flux, and pressure drop

Conference · Fri Jan 01 00:00:00 EST 1988 · Transactions of the American Nuclear Society; (USA)

OSTI ID:5530146

Rizwan-uddin,; Dorning, J J

Most previous stability analyses of two-phase flow in heated channels were restricted to the case in which total pressure drop, inlet temperature or enthalpy, and heat flux are constant in time. Linear (analytical) analyses for this case resulted in the determination of marginal stability boundaries (MSBs) in parameter space. Nonlinear asymptotic analyses showed that in most cases of practical interest supercritical Hopf bifurcation occurs resulting in stable limit cycles in the linearly unstable region, and numerical analyses of the dynamics equations showed the dependence of the limit cycle amplitude on the distance of the operating point from the MSB. Numerical analyses also have been carried out for time-dependent total (external) pressure drop and for various initial conditions. Some of these analytical and numerical analyses were carried out by first reducing the sets of partial differential equations (PDEs) for the single- and two-phase regions to a set of two coupled nonlinear integroordinary differential equations (ODEs) by integrating along the characteristics and along the channel length. This analytical reduction from PDEs to ODEs, before solving the problem numerically, greatly reduces the magnitude of the computations required. Hence, a similar analytical preprocessing of the basic equations is desirable for the more general case treated here in which total pressure drop, inlet temperature, and heat flux all can vary with time.

• OSTI ID: 5530146
• Report Number(s): CONF-881011-; CODEN: TANSA; TRN: 89-029256
• Journal Information: Transactions of the American Nuclear Society; (USA), Vol. 57; Conference: Joint meeting of the European Nuclear Society and the American Nuclear Society, Washington, DC (USA), 30 Oct - 4 Nov 1988; ISSN 0003-018X
• Country of Publication: United States
• Language: English

Related Subjects

22 GENERAL STUDIES OF NUCLEAR REACTORS
42 ENGINEERING
REACTOR KINETICS
TWO-PHASE FLOW
NONLINEAR PROBLEMS
HEAT TRANSFER
HYDRAULICS
PRESSURE DROP
REACTOR CHANNELS
REACTOR PHYSICS
STABILITY
TEMPERATURE DEPENDENCE
TIME DEPENDENCE
ENERGY TRANSFER
FLUID FLOW
FLUID MECHANICS
KINETICS
MECHANICS
PHYSICS
REACTOR COMPONENTS
220100* - Nuclear Reactor Technology- Theory & Calculation
420400 - Engineering- Heat Transfer & Fluid Flow