Project 03 · Case study
CFD validation · Heat transfer

Scraped-Surface Heat Exchanger CFD Validation

A two-dimensional ANSYS Fluent model benchmarked against published thermal-flow data for a scraped-surface heat exchanger.

  • ANSYS Fluent
  • Rotating reference frame
  • Heat transfer
  • GCI validation
ANSYS Fluent velocity magnitude contour for the scraped-surface heat exchanger model
Present CFDNū = 40.93
Published referenceNū = 40.60
Difference0.81%
Physical model

Reproducing the published configuration

The quarter-domain model represents aniline between a heated rotating shaft and a cooled stationary cylinder, with a narrow blade-tip clearance.

Published scraped-surface heat exchanger geometry and quarter-domain boundary-condition schematic
Reference geometry and reduced numerical domain used to reproduce the validation case.
GeometryD = 48.7 mm

Shaft diameter d = 8.7 mm and blade-tip gap δ/D = 0.025.

Operating pointRem = 1000

Pr = 56 with angular velocity 13.861 rad/s.

Thermal boundaries27.927 W/m²

Heat flux at the shaft and 283.15 K at the cylinder wall.

Numerical frameSteady rotating frame

Laminar forced convection solved without sliding-mesh remeshing.

Mesh independence

Refinement where the physics is steepest

Three structured meshes were compared using the area-averaged cylinder Nusselt number as the quantity of interest.

Coarse mesh · 231,614 elements
Medium mesh · 460,548 elements
Fine mesh · 946,536 elements
Fine mesh946,536elements
GCI0.187%fine / medium estimate
Refinement ratio≈ 1.4for successive grids
Asymptotic ratio1.06close to unity
Convergence

Residuals, heat balance and steady state

The final solution was checked using equation residuals and an independent wall heat-rate balance.

Residuals< 10−6
QT / QB0.9999873
|1 − QT/QB|1.27 × 10−5

The finite 0.1 mm blade thickness changes the theoretical Nusselt-based stopping criterion, so the wall heat balance provides the decisive steady-state check.

ANSYS Fluent scaled residual history showing final residuals below one times ten to the minus six
Final residual history through iteration 8910.
Published-data validation

Three checks against the reference study

Velocity, temperature and local Nusselt behaviour were compared directly with digitized reference data at Rem = 1000, Pr = 56 and δ/D = 0.025.

Normalized velocity profile comparing the CFD result with the published paper
Normalized velocity profile: close agreement across the blade-tip gap.
Normalized temperature profile comparing the CFD result with the published paper
Normalized temperature profile: larger deviation near the blade tip, where the thermal boundary layer is thinner.
Local Nusselt number distribution comparing the CFD result with the published paper
Local Nusselt behaviour remains nearly constant and follows the published trend.
Near-one-million-element showcase

A near-one-million-element flow-field showcase

A visual look at the near-one-million-element case highlights the resolved domain mesh, the blade-tip velocity-gap structure and a closer view of the local velocity field.

Near-one-million-element CFD mesh for the scraped-surface heat exchanger
Near-one-million-element mesh showing the resolved domain layout.
Velocity field near the blade-tip gap for the near-one-million-element case
Velocity field across the blade-tip gap at the resolved mesh scale.
Zoomed velocity contour for the near-one-million-element scraped-surface heat exchanger case
Zoomed local velocity contour showing the resolved gradient structure around the blade-tip region.
Engineering outcome

A validated model with 0.81% Nusselt difference

The Fluent model reproduced the reported heat-transfer level while independently demonstrating mesh convergence and thermal balance.

The remaining profile differences are concentrated near the blade-tip region, where mesh transition and the thin thermal boundary layer have the strongest influence.

  • CFD verification
  • Grid convergence
  • Thermal-flow validation
  • Rotating machinery
Validation reference Towards a better understanding of 2D thermal-flow processes in a scraped surface heat exchanger Blasiak & Pietrowicz · International Journal of Heat and Mass Transfer 98 (2016) · View published paper
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