Turbulent Forced Convection

Created using ANSYS 14.0

Problem Specification

This tutorial shows you how to simulate forced convection in a pipe using ANSYS FLUENT. The simulation corresponds to the forced convection experiment in MAE 4272 at Cornell University. The diagram shows a pipe with a heated section in the middle where constant heat flux is added at the wall. The ambient air is flowing into the pipe from the left with a uniform velocity. We'll use FLUENT to solve the relevant boundary-value problem and obtain the velocity, temperature, pressure and density distribution in the pipe. Inputs necessary for the simulation, such as the velocity at the pipe inlet and heat flux added at the wall, are obtained from one particular experimental run. Results from the simulation will be compared with corresponding experimental values. Background information is providedin this Powerpoint presentation from MAE 4272 at Cornell University. Your fingers might be itching to launch FLUENT and get busy with the mouse and keyboard. Nevertheless, you will be well-served by reviewing the presentation before proceeding. That way, you will be better able to apply the solution procedure to new problems.

Note to Cornell students enrolled in MAE 4272, Fall 2011:  It is best to run FLUENT in the ACCEL lab in the Engineering Library. The CIT labs in B7 Upson and 318 Phillips also have FLUENT. However, there is a video card incompatibility on the CIT computers that appears in the post-processing step. As a result, the temperature contours can look weird. Everything else works fine in the CIT labs. So, alternately, you can go through the simulation in the CIT labs, save your files and load them on to the ACCEL computers to obtain the correct temperature contours.

Simulation Inputs Obtained from Experiment

The following inputs are necessary to specify the domain, boundary conditions and material properties for the Boundary Value Problem (BVP) that we'll solve using FLUENT. The relevant BVP is discussed in presentation mentioned above.

Pipe Geometry:
Circular cross-section
Pipe radius = 2.94e-2 m
Pipe length = 6.045 m

Material Properties:
Coeff. of viscosity = 1.787e-5 kg/(m s)
Cp = 1005 J/(kg K)
Thermal conductivity = 0.0266 W/(m K)
Molecular weight = 28.97 g/mole

Inlet:
• u = 30.06 m/s
• v = 0 m/s
• T = 298.15 K
• k = 0.09 m2/s2; epsilon = 16 m2/s3 (These are not measured and are rough guess values)

Outlet:
• Pressure = 97225.9 Pa

Wall:
• Heating between x = 1.83 m and x = 4.27 m
• Wall heat flux = 5210.85 W/m2
• Wall roughness: 0 (assume smooth)
• Wall thickness: 0 (assume negligible)

Ambient conditions:
• Ambient pressure = 98338.2 Pa

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