# Module code: ENGT 5141 Assignment: CFD analysis in Heat transfer & combustion

This coursework item is: Summative
This summative coursework will be marked anonymously No
The learning outcomes that are assessed by this coursework are:
1 Demonstrate proficiency in analysing advanced thermal cycles and heat
transfer modes and their applications
2 Design and model heat and mass transfer on complex geometries using
commercial or in-house computational codes and critically evaluate the results

Tasks to be undertaken:
AIM
The overall aim of this assignment is to demonstrate that you have a clear understanding of
Thermal Analysis and Computational Fluid Dynamics (CFD) Methods, and the role these
techniques play in development of heat and mass transfer systems, the benefits associated with
their use and the problems and limitations encountered when using these methods.
The above aim is to be achieved through a written report, not exceeding 3000 words.
CASE STUDY 1
In a heat recovery system, Cold water enters the counter-flow helical heat exchanger at Tc,in o
C at
a rate of mA  kg/s, where it is used to recover heat from engine oil that enters the heat exchanger
at Th,in o
C at a rate of mB  kg/s. For the bench mark case use a pitch distance of 100mm for the
helical coil.
Each student will generate 2 case studies – A bench mark case which corresponds to the boundary
conditions in the table below – ( Use the row that matches the last ID of your student P No). And
another case where you optimise the design and operation of the heat exchanger. The objective
is to optimise the rate of heat transfer, within the constraints of 1m length and a fixed outer shell
diameter of 250mm. Flow rates must be realistic!
Figure 1: Schematic of Heat exchanger
Each student will use the following details for a base case and then optimise the heat transfer
Last Digit of
Student ID
Tc,in o
C Th,in o
C mA  kg/s mB  kg/s
0-1 5 120 4 8
2-3 7 110 4 9
4-5 10 100 4 10
6-7 12 90 4 11
8-9 15 80 4 12
Penultimate Digit
of Student ID
Tube diameter
(mm)
Shell diameter
(mm)
Interface
thickness (mm)
0-1 20 250 5
2-3 22.5 250 10
4-5 25 250 15
6-7 27.5 250 20
8-9 30 250 25
You will need to work through the following steps
1. Geometry Creation: using Ansys Design Modeller or importing from other CAD software
such as Creo, Solidworks. etc
2. Meshing the geometry: (Mesh)
3. Setting the boundary conditions: (setup)
4. Performing the simulation (Solution): Ansys fluent solver (steady state calculation)
5. Post processing the results:
CASE STUDY 2
The burner with the dimensions below should be built on meshed and solved in Ansys
workbench using a basic combustion model (for methane-air mixture or any other mixture the
student may opt to go for should be set in .
Figure 2: Burner Geometry
Last Digit of Student ID D(mm)
0-1 55
2-3 60
4-5 63.5
6-7 65
8-9 70
Figure 3: Burner Geometry 3D
Deliverables to be submitted for assessment: Written report
How the work will be marked:
Item Possible
Marks
Presentation/structure
Aims/Objectives should be stated clearly and concisely
Report should have clearly defined sections such as: Introduction, Review,
Methodology, Results/ Discussion, Conclusions, References, etc.
10
Introduction/background
Role of CFD and Computational Heat Transfer methods in modelling and design of
thermo-fluid systems
10
Review
The numerical methods used for convective heat transfer, combustion and fluid flow
(CFD) and the latest development in these fields the basic theoretical principles
underpinning modern computational Heat Transfer and CFD.
Role of CFD and Computational Heat Transfer methods in modelling and design of
thermo-fluid systems
10
Methodology
Mesh convergence and boundary conditions
Calculations to make decision and check results
25
Air
inflow
Fuel
inflow
Out-flow
Combustion
chamber
Results and Discussion
Discussing results of your case study: briefly interpreting and discussing the
results and comparing it to the bench mark.
General visualisation of the flow and temperature field may include:
Contours of velocity, temperature, pressure and any other relevant
parameter.
Vertical and axial profiles for velocity and temperature at specific location
of interest
Horizontal as well as cross-sectional images of velocity profiles coloured
with other variables.
You should demonstrate understanding of theory of Navier-Stokes equation of
motion and the various turbulence modelling used in CFD and in solving the 3D
convective heat transfer equation (steady state only).
Discuss the benefits that can be gained from using modern CFD and
Computational Heat Transfer methods
Discuss the limitations and problems associated with the use of CFD and
Computational Heat Transfer methods.
30
Conclusion 5
References/Appendices
At least 7 academic references
10
Total 100