cfd coursework 2023 your report shall be submitted in pdf format the a
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CFD Coursework 2023
Your report shall be submitted in pdf format (the
ANSYS Fluent files shall also be uploaded as a single
zip file read the guide for the simulations submission
- please do NOT zip the pdf report and the ANSYS
Fluent files into a single .zip file). Reports containing
more than 14-pages (excluding the cover page, table
of contents, references, appendix) will be penalized.
The report shall be prepared using the dedicated
template (which also includes the cover sheet and the
initial table where the student shall indicate which
questions have been addressed). According to the
University of Strathclyde regulations, all files will be
scanned using Turnitin to detect plagiarism issues.
Submissions of the coursework without the simulation
files will result in a 60% penalisation. The Ansys files
will be checked to verify that their contents reflect
what has been reported in the coursework and verify
that the associated license number is that released by
the University of Strathclyde (files prepared with
other licenses are not allowed). The report shall be
submitted no later than 12 noon Monday, March 25,
2024. After this time submissions will be penalised.
The maximum submission size is 500MB.
Submissions by email will not be considered. CFD Coursework 2023
Your report shall be submitted in pdf format (the
ANSYS Fluent files shall also be uploaded as a single
zip file read the guide for the simulations submission
- please do NOT zip the pdf report and the ANSYS
Fluent files into a single .zip file). Reports containing
more than 14-pages (excluding the cover page, table
of contents, references, appendix) will be penalized.
The report shall be prepared using the dedicated
template (which also includes the cover sheet and the
initial table where the student shall indicate which
questions have been addressed). According to the
University of Strathclyde regulations, all files will be
scanned using Turnitin to detect plagia
Somissions of the coursework we simulation
les will result in a 60% penalisation. The Ansys files
will be checked to verify that their contents reflect
what has been reported in the coursework and verify
that the associated license number is that released by
the University of Strathclyde (files prepared with
other licenses are not allowed). The report shale
Submitted no 120on Monday, March 25,
2024. After this time submissions will be penalised.
The maximum submission size is 500MB.
Submissions by email will not be considered./n/n DEPARTMENT OF MECHANICAL & AEROSPACE ENGINEERING
Coursework- Smoke Stack Chimney System
with Trickle Vents
Computer Aided Engineering and Design(16429)
Contents
1. Introduction
2. Geometry Size and Fluid Properties …………..
25
3. Simulation Set-up....
6
4. Analysis and final report........
6
5.
Notes/FAQ - other cues and suggestions to make your coursework
successful
9
6. References ..
10 DEPARTMENT OF MECHANICAL & AEROSPACE ENGINEERING
Smoke Stack Chimney System with Trickle Vents
1. Introduction
Chimney or smokestack configurations are widespread in the artificial environment. They are
a typical feature of modern society's fluid waste disposal methods as witnessed by the various
visible gaseous emissions into the atmosphere from domestic and industrial smokestacks
(McGrattan et al. [1]) and from cooling towers or mobile exhausts. Other 'non-visible' examples
are represented by the releases of liquid into coastal water, rivers and lakes from a variety of
(industrial, municipal and agricultural) sources, mining and oil extraction operations (Jirka [2];
Tomàs et al. [3]), chemical reactors and various plants for waste treatment and desalination
facilities (Oliver et al. [4]). Many other variants can be found in the specific field of energy
production, where such configurations are a characteristic feature of thermal discharges from
nuclear and fossil-fueled electricity generation plants (Martineau et al. [5]; Lee and Asce [6];
Fregni et al. [7]). They can also exist at a smaller scale in typical problems relating to the
cooling of computer mother boards and related CPUs and memories (Sun and Jaluria [8];
Biswas et al. [9]) or in combustion chambers as a result of the presence of holes or orifices for
fuel injection and dilution (Issac and Jakubowski [10]; Baltasar et al. [11]). Similar concepts
also apply to the manufacturing industry, where gas furnaces are commonly used for the heat
treatment of metals (Viskanta [12]). In the built (civil engineering) environment, such
configurations are widespread in emergency ventilation and air conditioning systems in
buildings (Venkatasubbaiah and Jaluria [13]; Subudhi et al. [14]; Morsli et al. [15,16]; Harish
[17]) and can be found, in general, in every technological situation in which a heat exchanger
is required.
Given the diversity and rich spectrum of circumstances in which such configurations can be
encountered and the myriad technological applications briefly reviewed above, generalizations
are rather difficult. Many situations are possible in principle depending on the specific case
considered. However, all these cases share a common factor, namely, the existence of
localized regions where the temperature is higher than that of the surroundings (typically the
area located at the bottom of the considered chimney or smokestack configuration). This
typically leads to the onset of "thermal convection" [18, 19] (heated fluid tends to become lighter
and therefore it rises through the chimney). Two fundamental situations are possible in
principle: Fluid rises in the chimney only due to thermal convection (completely "natural"
phenomenon), or a fixed mass flow rate is forced through the chimney (this leading to "mixed"
natural-forced convection through the chimney). Here, we will concentrate on mixed natural-
forced convection.
The considered configuration can be seen in Figure 1. This geometry has a symmetry plane.
It consists of a region (called “heat chamber”) delimited externally by walls with a constant
(high) temperature and an upper region of larger horizontal extension (the chimney) delimited
externally by adiabatic (no heat exchange) solid walls. The symmetry axis is indicated with a
dot-dashed line. The distance of the walls from the symmetry axis for the heat chamber and
the chimney is denoted by b and B, respectively (with B > b). Due to the heating effect of the
walls, the fluid inside the heat chamber expands (its density reduces) and therefore it becomes
“lighter”. The lighter hot fluid tends to rise in the heat chamber and enter the chimney region.
As the velocity of these naturally-induced currents is in general relatively small, this flow can
2 DEPARTMENT OF MECHANICAL & AEROSPACE ENGINEERING
be considered incompressible and the Boussinesq approximation can be used. Due to the fluid
rising through the heat chamber and the chimney, new colder fluid (having temperature Tc)
tends to be sucked into the heat chamber through the inlet region located at the bottom of the
heat chamber. However, the velocity of the rising currents can be enhanced by injecting some
air directly into the chimney as shown in Fig. 1 (forced flow aiding natural flow).
Moreover, the temperature of the air injected directly into the chimney can be modulated in
order to reduce the overall temperature of air released into the external atmosphere (e.g., by
injecting air at a temperature smaller than the ambient temperature Tc).
Cold
Fluid Injection
(Uforced Tforced)
B
Outlet
Hot
element
Chimney
Thot
Heat
chamber
Inlet
T
60
air
Figure 1 Schematisation of the Heat Chamber (channel)-Chimney system. The vector ğ is
the gravity acceleration
The characteristic numbers for natural (buoyant) and imposed (forced) flows are the Rayleigh
and Reynolds numbers, respectively, i.e.:
3 DEPARTMENT OF MECHANICAL & AEROSPACE ENGINEERING
Ra
=
gB+ATL³
να
U forced L
Re
=
V
where L is a reference length.
It is worth recalling that for an incompressible flow, the amount of fluid entering the system per
unit time is always equal to the amount of fluid leaving the system per unit time, (i.e. at any
instant an amount of relatively hot fluid leaves the system through the outlet section at the top,
which is equal to the amount of cold fluid entering the system from the bottom plus the fluid
injected from the side).
As shown in Fig.1, in general, the proper numerical simulation of this problem requires that the
numerical domain (the overall mesh) is not limited to the heat chamber and the chimney, it
must also include two extra areas corresponding to a certain portion of the external
environment (located under the heat chamber and over the chimney, respectively).
Table 1 Fluid properties for the Boussinesq model
Property
Assigned Value
Fluid
Air
Density Model
Boussinesq
Density (p)
Specific Heat (Cp) Model
Specific Heat (Cp)
Thermal Conductivity Model
Thermal Conductivity( λ)
Viscosity Model
1.225 Kg/m³
Constant
1006 J/KgK
constant
0.0242 W/mK
constant
Viscosity (μ)
1.7894x10-5 Kg/ms
Thermal Expansion Coeff. Model
Thermal Expansion Coeff.(BT)
Kinematic viscosity (v)
constant
0.0033 K-1
1.46x10-5 m²/s
Thermal diffusivity( a)
1.96x10-5 m²/s
+ DEPARTMENT OF MECHANICAL & AEROSPACE ENGINEERING
2. Geometry Size and Fluid Properties
210
15
25
5
70
40
40
15
09
60
60
08
X 25
40
40
50
30
70
Figure 2 Dimensions of the Heat Chamber-Chimney System (lengths are measured in
millimetres, they shall be multiplied by 10-3 in order to have the corresponding ones in
meters)
5