INTERNATIONAL JOURNAL OF MECHANICAL ENGINEERING AND TECHNOLOGY (IJMET) EFFECTS OF SUNLIGHT INTENSITY ON TURBO JET ENGINE OF AIRCRAFT

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1 INTERNATIONAL JOURNAL OF MECHANICAL ENGINEERING AND TECHNOLOGY (IJMET) International Journal of Mechanical Engineering and Technology (IJMET), ISSN (Print), ISSN (Print) ISSN (Online) Volume 5, Issue 3, March (214), pp IAEME: Journal Impact Factor (214): (Calculated by GISI) IJMET I A E M E 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 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) 31

2 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). (2) (3) 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 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] (4) (5) (6) 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 32

3 scale, Celsius, Fahrenheit, Kelvin, ect. The fundamental physical definition of temperature is provided by thermodynamic: [6] 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] (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. (8) 5. LAP LACE EQUATION For general equations of state, if classical mechanics is used, the speed of sound is given by[8] (9) where is the pressure and is the density and the derivative is taken adiabatically, where is the temperature in degrees Celsius ( C) 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]. (1) 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] (11) (12) 33

4 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: [1,11] where the left hand side is the initial amount of q flowing per unit time through surface S 1, the right hand side is the final amount through surface S 2, S 1 and S 2 are the vector areas for the surfaces S 1 and S 2 respectively. Notice the dot products are volumetric flow rates of q. 7. FLOW RATE Volume flow rate is defined by the [1] (13) (14) 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:[1,11] (15) 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 34

5 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 2 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 27 as shown in figure (3). Figure (3): combustor 35

6 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 1. 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, 36

7 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: (16) intake mass flow rate (17) fully expanded jet velocity (in the exhaust plume) aircraft flight velocity 37

8 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. I(intensity sun ligth)w/m ja fe m a m ju ju a s o n d I intensity sun ligth I intensity sun ligth month Figure (7): Average min and max of intensity sunlight for every month city of Krikuk 5 T(temperature) C ja fe m a m ju ju a s o n d T temperature month T temperature 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. 38

9 13. REFERENCE 1- J. L. Meriam and L. G. Kraige,"engineering mechanics dynamics ", 6 th editon. 2- R.C. Hibbeler,"engineering mechanics statics", 1 th edition 24 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", Yunus A,Cengel, Michael A. Boles, "thermodynamics an engineering approach" 5 th Edition. 7- Rowland S Benson," advanced engineering thermodynamics ", Petrovsky, I. G. "Partial Differential Equations. Philadelphia: W. B. Saunders" (1967). 9- Bloomfield, Louis, "How Things Work: The Physics of Everyday Life." (26). 1- Brown, Amy Christian, "Understanding Food: Principles and Preparation." (27). 11- Robert W. fox, Alan T. McDonald and Philip J. Pritchard,"Fluid mechanics", copyright 24 John Wiley & Sons, Inc. 12- Richard E. Sonntag, Claus Borrgnakke " Introduction to Engineering Thermodynamics," Irwin E. Treager "Aircraft Gas Turbine Technology", Jack L. Kerrebrock, The MIT Press" Aircraft Engines and Gas Turbines", Philip Walsh and Paul Fletcher, Wiley-Blackwell"Gas Turbine Performance", Yousif Khudhair Abbas, Automatic Refrigeration System for Break System of Aircraft, International Journal of Advanced Research in Engineering & Technology (IJARET), Volume 5, Issue 3, 214, pp , ISSN Print: , ISSN Online: