The reasons behind the raise of the temperature of turbo jet engine of aircrafts was investigated which leads to damaging the engine and costs the government huge expenses in case the plane is on ground and costs lives and expenses in case the aircraft is in flight. My daily study over the course of a year has proved the effect of sunlight on the temperature of turbo jet engine over the city of Kirkuk which lies on longitude 44.4 latitude 35.5.

1. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 – 6340(Print),
ISSN 0976 – 6359(Online), Volume 5, Issue 3, March (2014), pp. 31-39, © IAEME
31
EFFECTS OF SUNLIGHT INTENSITY ON TURBO JET ENGINE OF
AIRCRAFT
Yousif Khudhair Abbas
Assistant Lecture, Technology Collage Kirkuk
ABSTRACT
The reasons behind the raise of the temperature of turbo jet engine of aircrafts was
investigated which leads to damaging the engine and costs the government huge expenses in case the
plane is on ground and costs lives and expenses in case the aircraft is in flight. My daily study over
the course of a year has proved the effect of sunlight on the temperature of turbo jet engine over the
city of Kirkuk which lies on longitude 44.4 latitude 35.5.
1. INTRODUCTION
Airlines are of importance to the majority of countries nowadays for what they offer of great
and fast surface in transportation compared to the rest of transportation methods. In addition to the
existing attention and study given to this area the researcher asserts the importance of considering
and studying the sunlight energy in every city with airport for the effects of sunlight energy on the
performance of engines.
2. NEWTON'S LAWS OF MOTION
There are three physical laws that together laid the foundation for classical mechanics. They
describe the relationship between a body and the forces acting upon it, and its motion in response to
said forces. They have been expressed in several different ways over nearly three centuries, and can
be summarized as follows: [1, 2, 3]
1. First law: When viewed in an inertial reference frame, an object either remains at rest or
moves at a constant velocity, unless acted upon by an external force.
(1)
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2. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 – 6340(Print),
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2. Second law: The vector sum of the forces F on an object is equal to the mass m of that object
multiplied by the acceleration a of the object; thus, F = ma. Force and acceleration are both
vectors (as denoted by the bold type).
3. Third law: When one body exerts a force on a second body, the second body simultaneously
exerts a force equal in magnitude and opposite in direction on the first body.
3. EULER'S FIRST LAW
Euler's first law states that the linear momentum of a body, p (also denoted G) is equal to the
product of the mass of the body m and the velocity of its center of mass vcm: [4].
4. IDEAL GAS LAW
The ideal gas law is the equation of state of a hypothetical ideal gas. It is a good
approximation to the behavior of many gases under many conditions, although it has several
limitations. It was first stated by Émile Clapeyron in 1834 as a combination of Boyle's law and
Charles' law The ideal gas law is often introduced in its common form: .[5, 6, 7]
where P is the absolute pressure of the gas, V is the volume of the gas, n is the amount of
substance of gas (measured in moles), T is the absolute temperature of the gas and R is the ideal, or
universal, gas constant.
4-1. The Density
The volumetric mass density, of a substance is its mass per unit volume. The symbol most
often used for density is ρ (the lower case Greek letter rho). Mathematically, density is defined as
mass divided by volume:[5]
where ρ is the density, m is the mass, and V is the volume. In some cases (for instance, in the
United States oil and gas industry), density is loosely defined as its weight per unit volume, although
this is scientifically inaccurate – this quantity is more specifically called specific weight
4-2. Temperature
Is a numerical measure of hot and cold in a body that is in its own state of internal thermal
equilibrium. Its measurement is by detection of heat radiation or particle velocity or kinetic energy,
or by the bulk behavior of a thermometric material it may be calibrated in any of various temperature
(3)
(4)
2)(
)6(
5)(

3. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 – 6340(Print),
ISSN 0976 – 6359(Online), Volume 5, Issue 3, March (2014), pp. 31-39, © IAEME
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scale, Celsius, Fahrenheit, Kelvin, ect. The fundamental physical definition of temperature is
provided by thermodynamic: [6].
4-3. Specific volume
In thermodynamics, the specific volume of a substance is the ratio of the substance's volume
to its mass. It is the reciprocal of density and is an intrinsic property of matter:[7]
Specific Volume for an Ideal gas is also equal to the gas constant (R) multiplied by the
temperature and then divided by the pressure.
5. LAP LACE EQUATION
For general equations of state, if classical mechanics is used, the speed of sound is given by[8]
where is the pressure and is the density and the derivative is taken adiabatically,
where is the temperature in degrees Celsius (°C).
5-1. Specific weight
The specific weight (also known as the unit weight) is the weight per unit volume of a
material. The symbol of specific weight is γ (the Greek letter Gamma)[5].
Where
is the specific weight of the material (weight per unit volume, typically N/m3 units)
is the density of the material (mass per unit volume, typically kg/m3)
is acceleration due to gravity (rate of change of velocity, given in m/s2, and on Earth usually given
as 9.81 m/s2)
5-2. Pressure
Pressure is the amount of force acting per unit area. The symbol of pressure is p. Mathematically:[9]
)7(
(8)
(11)
9)(
(12)
)10(

4. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 – 6340(Print),
ISSN 0976 – 6359(Online), Volume 5, Issue 3, March (2014), pp. 31-39, © IAEME
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where:
is the pressure,
is the normal force,
is the area of the surface on contact.
6. ELEMENTARY VECTOR FORM
Consider the case when the surfaces are flat and planar cross-sections. For the case where a
velocity field can be applied, dimensional analysis leads to this form of the continuity equation:
[10,11]
where
• the left hand side is the initial amount of q flowing per unit time through surface S1, the right
hand side is the final amount through surface S2,
• S1 and S2 are the vector areas for the surfaces S1 and S2 respectively.
Notice the dot products are volumetric flow rates of q.
7. FLOW RATE
Volume flow rate is defined by the [10]
the flow of volume of fluid V through a surface per unit time t.
8. INCOMPRESSIBLE FLOW EQUATION
In most flows of liquids, and of gases at low Mach number, the density of a fluid parcel can
be considered to be constant, regardless of pressure variations in the flow. Therefore, the fluid can be
considered to be incompressible and these flows are called incompressible flow. Bernoulli performed
his experiments on liquids, so his equation in its original form is valid only for incompressible flow.
A common form of Bernoulli's equation, valid at any arbitrary point along a streamline, is:[10,11]
where:
is the fluid flow speed at a point on a streamline,
is the acceleration due to gravity,
is the elevation of the point above a reference plane, with the positive z-direction pointing
upward – so in the direction opposite to the gravitational acceleration,
is the pressure at the chosen point, and
is the density of the fluid at all points in the fluid
(13)
)15(
)14(

5. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 – 6340(Print),
ISSN 0976 – 6359(Online), Volume 5, Issue 3, March (2014), pp. 31-39, © IAEME
35
9. MAJOR PARTS OF TURBO JET ENGINE
The major parts of turbo jet engine are:
9-1. Air intake
can be designed to be part of the fuselage of the aircraft or integrated part of the nacelle .its
due to sucks in large quantities of air with reduce velocity and increase pressure as shown in figure
(1).
Figure (1) Air intake
9-2. Compressor
The compressor is the first component in the jet engine core. The compressor is made up of
fans with many blades and attached to a shaft. The compressor squeezes the air that enters it into
progressively smaller areas, resulting in an increase in the air pressure. This results in an increase in
the energy potential of the air. The squashed air is forced into the combustion chamber as shown in
figure (2).
Figure (2): compressor
9-3. Combustor
In the combustor the air is mixed with fuel and then ignited. There are as many as 20 nozzles
to spray fuel into the airstreams. The mixture of air and fuel catches fire. This provides a high
temperature, high-energy airflow. The fuel burns with the oxygen in the compressed air, producing
hot expanding gases. The inside of the combustor is often made of ceramic materials to provide a
heat-resistant chamber. The heat can reach 2700° as shown in figure (3).
Figure (3): combustor

6. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 – 6340(Print),
ISSN 0976 – 6359(Online), Volume 5, Issue 3, March (2014), pp. 31-39, © IAEME
36
9-4. Turbine
The high-energy airflow coming out of the combustor goes into the turbine, causing the
turbine blades to rotate. The turbines are linked by a shaft to turn the blades in the compressor and to
spin the intake fan at the front. This rotation takes some energy from the high-energy flow that is
used to drive the fan and the compressor. The gases produced in the combustion chamber move
through the turbine and spin its blades. The turbines of the jet spin around thousands of times. They
are fixed on shafts which have several sets of ball-bearing in between as shown in figure (4).
Figure (4): Turbine
9-5. Nozzle
The nozzle is the exhaust duct of the jet engine. This is the jet engine part which actually
produces the thrust for the plane. The energy depleted airflow that passed the turbine, in addition to
the colder air that bypassed the engine core, produces a force when exiting the nozzle that acts to
propel the engine, and therefore the airplane, forward. The combination of the hot air and cold air are
expelled and produce an exhaust, which causes a forward thrust. The nozzle may be preceded by a
mixer, which combines the high temperature air coming from the jet engine core with the lower
temperature air that was bypassed in the fan. The mixer helps to make the jet engine quieter as
shown in figure (5).[12,13]
Figure (5): nozzle
10. THEORY OF OPERATION
Gases passing through an ideal gas turbine undergo three thermodynamic processes. These
are isentropic compression, isobaric (constant pressure) combustion and isentropic expansion.
Together, these make up the Bray ton cycle .In a practical gas turbine, gases are first accelerated in
either a centrifugal or axial compressor. These gases are then slowed using a diverging nozzle known
as a diffuser; these processes increase the pressure and temperature of the flow. In an ideal system,

7. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 – 6340(Print),
ISSN 0976 – 6359(Online), Volume 5, Issue 3, March (2014), pp. 31-39, © IAEME
37
this is isentropic. However, in practice, energy is lost to heat, due to friction and turbulence. Gases
then pass from the diffuser to a combustion chamber, or similar device, where heat is added. In an
ideal system, this occurs at constant pressure (isobaric heat addition). As there is no change in
pressure the specific volume of the gases increases. In practical situations this process is usually
accompanied by a slight loss in pressure, due to friction. Finally, this larger volume of gases is
expanded and accelerated by nozzle guide vanes before energy is extracted by a turbine. In an ideal
system, these gases are expanded isentropic ally and leave the turbine at their original pressure. In
practice this process is not isentropic as energy is once again lost to friction and turbulence.
If the device has been designed to power a shaft as with an industrial generator or a
turboprop, the exit pressure will be as close to the entry pressure as possible. In practice it is
necessary that some pressure remains at the outlet in order to fully expel the exhaust gases. In the
case of a jet engine only enough pressure and energy is extracted from the flow to drive the
compressor and other components. The remaining high pressure gases are accelerated to provide a jet
that can, for example, be used to propel an aircraft .as shown in figure (6)[14,15]
Figure (6): Relation between velocity, temperature and pressure
A high specific thrust engine has a high jet velocity by definition, as the following
approximate equation for net thrust implies
where:
intake mass flow rate
fully expanded jet velocity (in the exhaust plume)
aircraft flight velocity
(16)
17)(

8. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 – 6340(Print),
ISSN 0976 – 6359(Online), Volume 5, Issue 3, March (2014), pp. 31-39, © IAEME
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11. TESTING AND CONCLUSIONS
Have measured the intensity of sun light and temperature for over a complete year in the
city of Kirkuk and the results were recorded in figures (7 and 8). The temperatures and light intensity
were averaged for months and we can observe they are related such that the sun light intensity and
temperature are greatest in July and August. When we apply equation (16) the thrust of the engine is
less than usual the reason value of aircraft flight velocity (Va) its bigger because of high temperature.
0
200
400
600
month
I(intensitysunligth)w/m2
I intensity sun ligth
I intensity sun
ligth
30
0
32
0
38
0
43
0
49
0
50
0
50
0
50
0
46
0
41
0
27
0
16
0
ja fe m a m ju ju a s o n d
Figure (7): Average min and max of intensity sunlight for every month city of Krikuk
0
10
20
30
40
50
month
T(temperature)C
T temperature
T temperature 9 11 14 23 28 34 39 37 32 25 17 12
ja fe m a m ju ju a s o n d
Figure (8): Average min and max of temperature for every month city of Kirkuk
12. RECOMMENDATIONS
Studies to be conducted on the effect of sunlight in cities or areas where airports exist.

9. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 – 6340(Print),
ISSN 0976 – 6359(Online), Volume 5, Issue 3, March (2014), pp. 31-39, © IAEME
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13. REFERENCE
1- J. L. Meriam and L. G. Kraige ,"engineering mechanics dynamics ", 6th
editon.
2- R.C. Hibbeler,"engineering mechanics statics", 10th
edition 2004 by pearson education, Inc.
3- Browne, Michael E. "Schaum 's outline of theory and problems of physics for engineering
and science "(July 1999).
4- Feynman, Richard P. "The Feynman Lectures on Physics" (1977).
5- Myron Kaufman, "principle of thermodynamic", 2002.
6- Yunus A ,Cengel, Michael A. Boles, "thermodynamics an engineering approach" 5th
Edition.
7- Rowland S Benson," advanced engineering thermodynamics ", 1977.
8- Petrovsky, I. G. "Partial Differential Equations. Philadelphia: W. B. Saunders" (1967).
9- Bloomfield, Louis, "How Things Work: The Physics of Everyday Life." (2006).
10- Brown, Amy Christian, "Understanding Food: Principles and Preparation." (2007).
11- Robert W. fox, Alan T. McDonald and Philip J. Pritchard ,"Fluid mechanics", copyright 2004
John Wiley & Sons, Inc.
12- Richard E. Sonntag, Claus Borrgnakke " Introduction to Engineering Thermodynamics," 2007.
13- Irwin E. Treager "Aircraft Gas Turbine Technology", 1979.
14- Jack L. Kerrebrock, The MIT Press" Aircraft Engines and Gas Turbines", 1992.
15- Philip Walsh and Paul Fletcher, Wiley-Blackwell"Gas Turbine Performance", 2004.
16- Yousif Khudhair Abbas, “Automatic Refrigeration System for Break System of Aircraft”,
International Journal of Advanced Research in Engineering & Technology (IJARET),
Volume 5, Issue 3, 2014, pp. 47 - 55, ISSN Print: 0976-6480, ISSN Online: 0976-6499.