This document discusses simulations of cooling a telecommunications cabinet prototype using computational fluid dynamics (CFD). It presents the following key points: 1) A CFD model was created using GAMBIT meshing software to simulate air flow and heat transfer within a telecommunications cabinet measuring 0.65x0.65x0.30 m containing a heating element. 2) Simulations were run with and without ventilation openings, showing ventilation is needed to maintain safe temperature levels inside the closed cabinet. 3) Forced convection cooling via an air inlet and outlets was able to maintain air temperatures of 309-311K, an improvement of 8-10K over the natural convection scenario without openings.

1. CFD SIMULATION OF
TELECOMMUNICATIONS CABINET
Mokrane mehdi, Ouali Maamar, Hatref Nasrine
Unité de Développement des Equipements Solaires, UDES, Centre de Développement des Energies Renouvelables,
CDER, 42004, Tipaza, Algerie
mok.mehdi@gmail.com
Abstract— GSM or UMTS equipment installed in a normal
basic telecommunications cabinet or control unit dissipates
large amount of heat. Because of compaction technology
and advancement in the field of communication, cooling
telecommunications cabinets becomes a great challenge for
thermal engineers. This article presents the results of
simulations on cooling a telecommunication cabinet
prototype using a numerical computer code: CFD
"Fluent".
Keywords: telecommunication cabinet, heat transfer, cooling,
CFD, Fluent
I. INTRODUCTION
This work focuses on the study of an air conditioning system
and solar cooling of relay antenna GSM (Global System for
Mobile Communications) especially the BTS (Base
Transceiver Station) The first active electronic component of
GSM mobile network (2G). However, there is the
implementation of new, more efficient antennas, namely, the
Node-B and the eNode-B respectively, to the networks (3G)
and (4G). The installation of these stations, in hot areas, and
remote sites, requires adaptation the last to the specific
climatic conditions regions. Thermal control of electrical and
electronic cabinets GSM stations, also presents difficulties.
That can lead to the heating problems. These problems result
by temperature spikes equipment used above limited values
Fixed by the standards or related to the holding of certain
component. . The study of heat transfer main objective to
determine the optimum cooling of the cabinet, account
keeping of these characteristics and the operating
environment. Several cooling methods are used. The choice of
methods depends on the power developed by the component
of the cabinet, as well as the climatic conditions of city,
without forgetting the energy factor related directly to the
cooling capacity of the installed system. In 1991 G.F.
Robertson cited eight criteria of choice, thermal efficiency,
plant size, reliability, vibration, cost, nuisance, maintenance
and electrical interference component to be cooled. [1] These
cooling techniques are divided into two large families passive
cooling and cooling active voice vote. The distribution is done
principally on the low energy consumption of the cooling
system. We note, by heat pipe cooling. In 2002, Y. et al
Avenas showed interest for applying miniature heat pipes with
a high thermal conductivity is well adapted to the heat
dissipation of electronic components [2]. Thermosyphon
cooling or cooling by immersion in a dielectric fluid, Forgot
without air cooling with temperature gradient. . The spray
cooling has been studied by a number of researchers [3-5] as a
thermal management tool high heat flow, And the
impingement cooling mist [6-8]. The use of the phase change
principle using latent heat material (PCM) we offered a very
good possibility of energy rationalization. Many researcher
have studied the thermal performance of PCM in [9], [10]
Y.Wang et al, conducted a computer simulation of a hybrid
heat sink fins multi type PCM in three dimensions to
understand the thermal heat dissipation transient. The study
showed that the operating temperature can be well controlled
by the presence of phase change material [11]. S.Mallik et al,
studied the thermal management of PCM applied in the
electronic control unit of the car [12]. Finally a thermal
simulation was conducted using a numerical calculation code:
CFD "Fluent”, based on the principle of finite volumes, in
order to determine the thermal distribution flow and heat
transfer within the BTS cabinets. To remedy has the
increasing flux densities to be dissipated. As well as the
outside temperatures location city.
II. MODEL CFD
The use of CFD model is done in two steps. The first step is
primarily the creation of the geometry or the computation
domain and its mesh. We use a commercial gambit 2.3 mesh.
The domain calculates is represented by a dimension cabinet
(0.65 * 0.65 * 0.30) m with a working volume of about 1.3 m3
and heat sink with size (0.03 * 0.20 * 0.36) m placed in the
middle of the cabinets. The second step concerns the
resolutions of the Navier -Stocks and energy it is conducted
with the help of a fluent CFD solver 6.3 based on the principle
of finite volumes. The turbulent viscosity model k-ε is chosen.
The dimensions of the geometry of the cabinet and a mesh size
his represents on figure1.
Fig1.Domain calculated and meshes
Heating boxes

2. 302.8
303
303.2
303.4
303.6
303.8
304
304.2
304.4
304.6
1 100001 200001 300001 400001 500001 600001 700001 800001 900001 1000001
Temperature(T)
Nombre de maille (N)
T=f(N)
A second geometry is designed with openings an air inlet of
square form (0.1 * 0.1) m is placed at the lower wall of the
cabinet Two extraction openings of the same diameter each
(outlet1 and outlet2) are placed on the top wall (Figure.2).
Fig.2. Diagram of the cabinet with and without openings
The mesh grid is provides the quadrilateral shape of mesh
elements about 100,000 to 1 million element. . To ensure that
the results obtained its independence mesh see figure 2. Our
choice is to round mesh element 600000.
Fig.3. Independence mesh
A. Mathematical formula and boundary conditions
The equations governing conservations for mass,
momentum and energy, and k and ε can be expressed as
follows:
- Continuity
- Movement
- Energy
- Turbulent kinetic energy (k)
- Dissipation rate (ε)
The boundary conditions adopted for this simulation has a heat
flux convective at the walls of the cabinet and a fixed
temperature of the heated blade. This value is fixed at TL =
323 K according to the literature. In the second configuration
we apply an air stream at temperature of Tm = 308K with a
speed of 24 m / s and a pressure in the output equal to the
atmospheric pressure with the same conditions on the cabinet
and heating boxes. Telecommunications cabinet lies in the
confinement of the air inside the cabinet
III. RESULTS AND DISCUSSION
We conducted a numerical simulation to observe the evolution
and distribution of temperature fields inside a cabinet.
Maximum temperature TL= 323 K is required at the heating
boxes with a convective heat flux on the walls of the cabinet.
The temperature of the external environment is around Te =
318K, with a convective heat transfer coefficient h = 15 W /
m2
K. The first part relates to the simulation of the cabinet
with natural convection mode without opening at the walls,
the second part, offers a simulation of heat transfer
phenomenon with forced convection mode, with a square
shaped air inlet (0.1 * 0.1) m and temperature T = 308K, at the
lower wall of the cabinet with two extraction openings of the
same diameter each, placed on the upper wall (Figure.2). Air
is connected using a fan with a constant speed of 24m / s.
Solving the equations of coupled phenomena in transient
regime is very complicated. 3D CFD simulation computer
code using the finite volumes offered an alternative interest to
work around this complexity. The simulation of the
phenomenon will fixed us on the development the associated
thermal fields our study will allow us to explore different
configuration plans with the integration of several parameters,
namely the power of the heating boxes and the temperature of
the entering air, as well as solar radiation onto the walls of the
cabinet .The Figure.4 compares the simulation results of
changes in temperature as a function of the position x to z =
0.55 and y = 0.10 (Figure.2) for both configurations with and
without cooling over time. The simulation show that in the
case of a cabinet of natural convection mode without opening
at the walls the maximum and minimum temperature of the air
flowing to the left and right boxes at t = 15s of 311-317 K, 316
to 320K for t = 318 to 322K 30s and t = 45s and t = 60s. The
increase in air temperature in the cabinet confirms the
advantage of using cooling systems using forced convection.
The air temperature inside the cabinet is about 309 to 311K for
t = 15s to T = 60s. A decrease is observed after 60s 10K
between the two configurations for the highest temperatures
recorded near the heated blade. Temperatures on the
observation line have a difference of 8K (Figure.5). The
cooling system has an essential role to control the air
temperature in the cabinet.

3. t= 15s t= 30s
t= 45s t= 60s
(a) (b)
Fig.5. Temperature field on the plane (x, z) to y = 0.15 after 60s
(a) Without cooling, (b), With Cooling
………without cooling
……… with cooling
Fig.4. Evolution of the temperature profile as a function of the position x = 0 m, z = 0.55 and
y = 0.10m in time for the two configurations with and without ventilation.

4. IV. CONCLUSION
The results of numerical simulations were used to observe the
effect of increasing the temperature within the cabinet which
is subjected to a relatively high flow and without cooling. The
air temperature in the presence of heating elements and in a
closed system varies the density of the latter. The air lighter
and hotter occupies the upper part of the cabinet. Non mastery
of severe climate changes forces us to integrate a cooling
system. The axial convection heat density and discharge is
essential to maintain the temperature of the heating elements
and to reduce the air temperature in the cabinet. Heat transfer
results from this study highlight the thermal performance
cooling system by forced convection for the thermal
management of telecommunications closets. For future work,
we plan to integrate other cooling techniques to further reduce
the air temperature in the cabinet.
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