Radiant Floor Heating System, Paper CFD Validation by ANSYS Fluent Simulation Training

Rated 0 out of 5
(be the first to review)


The present problem validates the paper [Numerical study on impact of non-heating surface temperature on the heat output of radiant floor heating system] results, using CFD simulation by ANSYS Fluent software.

This product includes Geometry & Mesh file and a comprehensive Training Movie.

There are some free products to check our service quality.

To order your ANSYS Fluent project (CFD simulation and training), contact our experts via [email protected], online support, or WhatsApp.


Paper Description

The present problem simulates heat transfer in a room through an radiant underfloor heating system using ANSYS Fluent software. This simulation is based on an article [Numerical study on impact of non-heating surface temperature on the heat output of radiant floor heating system]. CFD simulation results are compared with the paper results and validated. Simulation is performed for case 1 mode of this paper. According to Table 2 of the paper, the water inlet temperature is defined as 35 ºC, the water inlet mass flow rate is equal to 37.4 gs-1, and the ceiling and other walls temperature of the room are equal to 16.8 ºC. In fact, in this project, a room has been designed in which a floor heating system has been installed on the floor of this room to create heating inside the room.

This underfloor heating system consists of a pipe that twists in horizontal directions and covers the floor’s entire surface. The flow of water inside the pipe has significant heat, and the occurrence of heat transfer from the outer surface of this pipe to the air inside the room causes the heating of the ambient air. A hot water flow with a mass flow rate of 0.0374 kg.s-1 and a temperature of 35 ºC enters the pipe and passes through a path full of screws inside the pipe to have an excellent opportunity to transfer heat to the room environment. Also, the radiation model has been used to apply heat radiation from the walls of the room and the pipes of the heating system, etc. To define radiation, the DO (discrete ordinates) model has been used.

This model is known as the most comprehensive model for the definition of radiation and has a high-resolution accuracy. The radiative heat transfer equations for a discrete number of finite solid angles are solved when using this model.

Floor Heating Geometry & Mesh

The present model is designed in three dimensions using SOLIDWORKS software and Design Modeler. The geometry of this model consists of a room on the floor of which there is a spiral tube. The room has a length and width of 4 m and 3 m, and its height is equal to 2.8 m. The pipe has a diameter of 2 cm.


The meshing of the present model has been done using ICEM software. The mesh type is hybrid; meshing is a combination of structured and unstructured mesh. Structured mesh is used inside the pipe’s interior and the outer layer of the pipe, and most of the interior of the room; While in a limited part of the outer space of the pipe, the unstructured mesh is used. Finally, the number of cells produced is equal to 3744855.


Radiant Floor Heating CFD Simulation

We consider several assumptions to simulate the present model:

  • We perform a pressure-based solver.
  • The simulation is steady.
  • The gravity effect on the fluid is equal to -9.81 m.s-2 along the vertical axis.

The following table represents a summary of the defining steps of the problem and its solution:

Viscous Model k-epsilon
k-epsilon model RNG
near-wall treatment Menter-Lechner
Radiation Model Discrete Ordinates (DO)
Energy On
Boundary conditions
Inlet-Water Mass Flow Inlet
mass flow rate 0.0374 kg.s-1
temperature 35 ºC
Outlet-Water Outflow
flow rate weighting 1
Walls-Room Wall
wall motion stationary wall
temperature 16.8 ºC
internal emissivity 0.9
BC type opaque
Wall-Pipe Wall
wall motion stationary wall
thermal condition coupled
internal emissivity 1
BC type opaque
Pressure-Velocity Coupling SIMPLEC
pressure PRESTO
momentum first order upwind
turbulent kinetic energy first order upwind
turbulent dissipation rate first order upwind
energy first order upwind
discrete ordinates first order upwind
Initialization methods Hybrid

Validation Results

The validation of the present simulation is based on Tables 5 and 6 of the mentioned article. The value of the outlet temperature of the pipe is extracted from case 1 of Table 5 of the paper. It is compared with the value of the temperature calculated in this simulation through the area-weighted average at the outlet boundary of the pipe. Also, the amount of heat output power on the surface of the pipe is extracted from case 1 of Table 6 of the article. It is compared with the heat transfer rate calculated in this simulation through the total heat transfer rate on the outer surface of the pipe. The following table shows the comparison between the results in the paper and the present numerical simulation results.

Error (%) present CFD simulation paper experimental  
0.193 31.439 31.5 Outlet Water Temperature (ºC)
1.911 556.839 546.4 Total Heat Output (W)

Also, after the completion of the solution process, we obtain three-dimensional contours related to the temperature inside the room and the tube, and the heat flux contour on the outside surface of the tube. Meanwhile, a two-dimensional plate is drawn so that it passes through the middle of the heating pipe. A two-dimensional contour of temperature is obtained on this two-dimensional plate. These contours will indicate the occurrence of heat transfer. According to the resulting contours, heat is transferred from the outer surface of the pipe to the interior of the room and causes heating of the air inside the room.

You can obtain Geometry & Mesh file, and a comprehensive Training Movie which presents how to solve the problem and extract all desired results.


There are no reviews yet.

Leave a customer review

Your email address will not be published. Required fields are marked *

Back To Top

Refund Reason

Call On WhatsApp