VMFL039

VMFL039
Boiling in a Pipe with Heated Wall

Overview

Reference G.G. Bartolomei, V.M. Chanturiya "Experimental Study of True Void Fraction When Boiling Subcooled Water in Vertical Tubes". Thermal Engineering. Vol. 14, pp. 123-128, 1967.

Solver Ansys Fluent, Ansys CFX

Physics/Models Multiphase flow, phase change, RPI Wall boiling Model

Input File

wall-boiling.def for Ansys Fluent

VMFL039___wall-boiling.def for Ansys CFX

Project Files Link to Project Files Download Page

Test Case

Bubble formation and boiling near the heated wall of a vertical pipe are modeled. Outer wall of the pipe is heated with a constant heat flux.

Figure 99: Flow Domain

Material Properties	Geometry	Boundary Conditions
Steam-Water 2-phase Flow: Water: continuous phase Water Steam: dispersed bubbles Bubble diameter dependent on fluid temperature	Radius of the pipe = 7.7 mm Height of the pipe = 2 m	Mass flux at inlet = 900 kg/m²/s Inlet pressure = 4.5 X 10⁶ N/m² Heat transfer at the wall = 570000 W/m²

Material Properties

Geometry

Boundary Conditions

Steam-Water 2-phase Flow:

Water: continuous phase
Water Steam: dispersed bubbles

Bubble diameter dependent on fluid temperature

Radius of the pipe = 7.7 mm

Height of the pipe = 2 m

Mass flux at inlet = 900 kg/m²/s

Inlet pressure = 4.5 X 10⁶ N/m²

Heat transfer at the wall = 570000 W/m²

Analysis Assumptions and Modeling Notes

The flow is steady. SST model is used for turbulence. RPI model for wall boiling is used with a value of 0.8 for the wall area fraction affected by vapor.

Results Comparison Ansys Fluent

Figure 100: Comparison of Temperature Along the Pipe Wall

Results Comparison Ansys CFX

Figure 101: Comparison of Temperature Along the Pipe Wall