Analytical study of flow instability behaviour in a boiling two-phase natural circulation loop under low quality conditions
-
A. K. Nayak
Abstract
Analytical investigations have been carried out to study the flow instability behaviour in a boiling two-phase natural circulation loop under low quality conditions. For this purpose, the computer code TINFLO-S has been developed. The code solves the conservation equations of mass, momentum and energy and equation of state for homogeneous equilibrium two-phase flow using linear analytical technique. The results of the code have been validated with the experimental data of the loop for both the steady state and stability. The study reveals that the stability behaviour of low quality flow oscillations is different from that of the high quality flow oscillations. The instability reduces with increase in power and throttling at the inlet of the heater. The instability first increases and then reduces with increase in pressure at any subcooling. The effects of diameter of riser pipe, heater and the height of the riser on this instability are also investigated.
Abstract
Das Strömungsverhalten einer siedenden Zweiphasenströmung in einer Schleife mit Naturumlauf unter Bedingungen niedriger Qualität wurde analytisch untersucht. Dazu wurde der Computer-Code TINFLO-S entwickelt. Der Code löst die Erhaltungsgleichungen von Masse, Implus und Energie sowie die Zustandsgleichung für eine Zweiphasenströmung im homogenen Gleichgewicht mit Hilfe linearer analytischer Verfahren. Die Studie zeigt, dass das Stabilitätsverhalten von Strömungsoszillationen niedriger Qualität verschieden ist von dem Verhalten bei hoher Qualität. Die Instabilität verringert sich mit einer Erhöhung der Leistung am Eingang der heißen Zone. Die Instabilität erhöht sich zuerst und erniedrigt sich dann mit steigendem Druck bei jeder Unterkühlung. Der Einfluss von Durchmesser und Höhe des Steigrohres, sowie der heißen Zone auf die Instabilität wurde ebenfalls untersucht.
Nomenclature
- A
cross-sectional area (m2)
- Cp
specific heat (J/kg K)
- D
hydraulic diameter (m)
- f
Darcy friction factor
- g
acceleration due to gravity (m/s2)
- h
specific enthalpy (J/kg)
- hfg
latent heat of vaporisation (J/kg)
- L
length of section (m)
- p
pressure (N/m2)
- Δp
pressure drop (N/m2)
- qh
heat applied/unit volume of coolant (W/m3)
- s
growth rate of perturbations time (s)
- T
temperature (K)
- Tsat
saturation temperature (K)
- v
specific volume (m3/kg)
- w
mass flow rate (kg/s)
- x
axial distance (m)
Greek symbols
- σ
volumetric thermal expansion coefficient (K–1)
- μ
dynamic viscosity (N s/m2)
- ρ
density (kg/m3)
- τ
residence time of fluid (s)
- Δ
Difference
Subscripts
- av
average
- c
channel
- d
downcomer
- f
saturated liquid
- g
saturated vapour
- in
inlet of section
- L
over section length
- ss
steady state
- ss,av
average steady state
- vfg
(vg – vf) (m3/kg)
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© 2002 Carl Hanser Verlag, München
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Articles in the same Issue
- Frontmatter
- Calendar of Events
- Calendar of events . Veranstaltungskalender
- Summaries
- Summaries
- Books
- Safety Assessment and Verification for Nuclear Power Plants
- 3D numerical investigation of natural circulation between the reactor pressure vessel and the cooling pond of a VVER-440 type reactor in incidental conditions during maintenance
- A process-oriented simulation model for common cause failures
- Books
- Books · Bücher
- Simulation of pulsed neutron activation for determination of water flow in pipes
- Books
- Books · Bücher
- Adjoint P1 equations for neutron slowing down
- Books
- Bücher · Books
- Experimental and numerical investigation of sub-cooled boiling, condensation, and void flashing in nuclear heating reactor test loop
- Analytical study of flow instability behaviour in a boiling two-phase natural circulation loop under low quality conditions
- Books
- Bücher · Books
- Thermal hydraulic analysis and design of the WWR-M2 nuclear research reactor – power upgrading
- Books
- Books · Bücher
- Simulation of the gamma dose rate in a loss of pool water accident of the second Egyptian research reactor ET-RR-2
- Behaviour of electrical cables under fire conditions
- Books
- Better integration of radiation protection in modern society.
- Berechnungsverfahren für Temperaturen im Brandnahbereich
- Books
- Modifications to Nuclear Power Plants
- Alerting procedures for scenarios without warning times
- Technical Note
- Approximation of solitary burn-up waves by generalized Gompertz functions
- Advances · Patente
- Patent
- Note · Mitteilung
- Notes
