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Essays about heat transfer
Essays about heat transfer
Practical report on heat transfer
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1.1 GENERAL BACKGROUND
Heat transfer is by virtue thermal energy stored in temperature-dependent motion of particles. The exchange of kinetic energy of particles occurs through the boundary between two systems which are at different temperatures from each other or from their surroundings. Heat transfer constantly occurs from a region of high temperature to the region of lower temperature. Heat transfer changes the internal energy of both systems according to the Thermodynamics. The Second Law of Thermodynamics defines the concept of thermodynamic entropy. Heat transfer is the study of thermal energy transport within a medium or among neighboring media by molecular interaction, fluid motion, and electro-magnetic waves, resulting from a spatial
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in chemical operations, minimization of building heat losses using improved insulation techniques, thermal control of space vehicles, heat treatment of metals, dispersion of atmospheric pollutants. A thermal system contains matter or substance and this substance may change by transformation or by exchange of mass with the surroundings. To perform a thermal analysis of a system, we need to use thermodynamics, which allows for quantitative description of the substance. This is done by defining the boundaries of the system, applying the conservation principles, and examining how the system participates in thermal energy exchange and …show more content…
Convection more likely occurs with a greater variation in density between the two fluids, a larger acceleration due to gravity that drives the convection through the convecting medium. Radiation describes any process in which energy emitted by one body travels through a medium or through space absorbed by another body. Radiation occurs in nuclear weapons, nuclear reactors, radioactive radio waves, infrared light, visible light, ultraviolet light, and X-rays
Thermodynamics is essentially how heat energy transfers from one substance to another. In “Joe Science vs. the Water Heater,” the temperature of water in a water heater must be found without measuring the water directly from the water heater. This problem was translated to the lab by providing heated water, fish bowl thermometers, styrofoam cups, and all other instruments found in the lab. The thermometer only reaches 45 degrees celsius; therefore, thermodynamic equations need to be applied in order to find the original temperature of the hot water. We also had access to deionized water that was approximately room temperature.
When there is a heat exchange between two objects, the object’s temperature will change. The rate at which this change will occur happens according to Newton’s Law of heating and cooling. This law states the rate of temperature change is directly proportional between the two objects. The data in this lab will exhibit that an object will stay in a state of temperature equilibrium, unless the object comes in contact with another object of a different temperature. Newton’s Law of Heat and Cooling can be understood by using this formula:
Heat is the total energy of molecular motion in a substance while temperature is a measure of the average energy of molecular motion in a substance. From this we can determine the heated molecules inside of a bouncy ball giving us its great effect on its given height when dropped at its designated height. A lower temperature will lead to a lower pressure. As the temperature decreases, gas molecules contract and move around more slowly with less energy. Thus, lower pressure leads to a lower bounce of the ball. This then lead onto room temperature, the molecules inside of the bouncy ball remain the same, as there has not been any temperature used to affect the bouncy ball.
These days muscle pain and spasms have become the most common complaint of many working men and women. To avoid this pain most of them rely upon spa’s to lessen their pain. One of the main techniques used in the spa’s to reduce muscle pain is heat therapy. This nonpharmacological technique helps in reducing the muscle pain as it vasodilates the muscle causing the blood flow to increase at the site of inflammation or injury (Mohammadpour et al. 2014). Due to an increase in the blood supply, the oxygen levels also rise which reduces the amount of inflammatory facilitators and triggers heat shock proteins. With the latest rehabilitation benefits, heat therapy is being used for curing many problems because of its positive feedback.
The porpoise of these is to determine the Specific Heat. Also known as Heat Capacity, the specific heat is the amount of the Heat Per Unit mass required to raise the temperature by one degree Celsius. The relationship between heat and temperature changed is usually expected in the form shown. The relationship does not apply if a phase change is encountered because the heat added or removed during a phase change does not change the temperature.
Conduction, convection and radiation are the three methods through which heat can be transferred from one place to another. The (www.hyperphysics.com) first method is the conduction through which heat can be transferred from one object to another object. This process is defined as the heat is transmitted from one to another by the interaction of the atoms and the molecules. The atoms and the molecules of the body are physically attached to each other and one part of the body is at higher temperature to the other part or the body, the heat begins to transfer. A simple experiment through which conduction can be understood easily is as follows. First of all, take a metallic rod of any length. Hold the rod in the hand or at any stand made up of the insulator so that the heat does not transfer to the stand. Heat up the one end of the rod with the help of the spirit lamp. After sometime, touch the other end of the end, the other end of the becomes heated too and the temperature of the other end of the rod has also increased. Although only one end of the rod is heated with the spirit lamp, but the other end of the rod has also been heated. This is represents that the heat has been transferred from one end of the rod to the other end of the rod without heating it from the other end. So, the transformation of the heat is taking place. This process is called the conduction. Conduction is a process which is lead by the free electrons. As the conduction happens occurs only in the metallic materials, the reason for it is that the metals has the free electrons and they can move freely from one part of the body to another part of the body. These electrons are not bounded by the nucleus so, they can move easily. And when the temperature of the ...
The heat makes the molecules in the mixture expand and move slower than when they are in colder temperatures (source 1). The molecules are like people when it comes to how they react to heat and coldness. When the molecules are cold, they like to be very close to one another and the molecules move fast because they are “shivering” (source 2).This is just a one of many examples and comparisons that I am going make throughout this paper. Some of the examples will be very cheesy. I am going to give a warning. When the molecules are hot, they like to be far apart from one another (source 1). They even might start to sweat like humans, too. The molecules have some energy too, but the molecules just do not have as much energy when they are hot. They like to be lazy like many humans do in hot weather (source 1).
I will start by discussing entropy. Entropy is a tricky topic and can be easily misunderstood. Perhaps this is because entropy has two different meanings. One definition of entropy is one used for a thermodynamic system involved
Conduction, Convection, and Radiation Heat transfer is the way heat moves through matter to change the temperature of other objects. There are three types of heat transfers, Conduction, Convection, and Radiation. The first kind of heat transfer, conduction, is heat transferring through direct contact of materials. This would be the same thing as a pan on the stove. The heat from the stove touches the pan directly, therefore making the pan hot.
A thermostat is a device, which is designed to provide and regulate a certain temperature in the room or apartment, thereby creating comfortable and optimal for human life living conditions in it. Thermostat gives the possibility to set and control the temperature of heating devices.
Thermodynamics is the branch of science concerned with the nature of heat and its conversion to any form of energy. In thermodynamics, both the thermodynamic system and its environment are considered. A thermodynamic system, in general, is defined by its volume, pressure, temperature, and chemical make-up. In general, the environment will contain heat sources with unlimited heat capacity, allowing it to give and receive heat without changing its temperature. Whenever the conditions change, the thermodynamic system will respond by changing its state; the temperature, volume, pressure, or chemical make-up will adjust accordingly in order to reach its original state of equilibrium.
As discussed in class, submission of your solutions to this exam will indicate that you have not communicated with others concerning this exam. You may use reference texts and other information at your disposal. Do all problems separately on clean white standard 8.5” X 11” photocopier paper (no notebook paper or scratch paper). Write on only one side of the paper (I don’t do double sided). Staple the entire solution set in the upper left hand corner (no binders or clips). Don’t turn in pages where you have scratched out or erased excessively, re-write the pages cleanly and neatly. All problems are equally weighted. Assume we are working with “normal” pressures and temperatures with ideal gases unless noted otherwise. Make sure you list all assumptions that you use (symmetry, isotropy, binomial expansion, etc.).
Heat energy is transferred through three ways- conduction, convection and radiation. All three are able to transfer heat from one place to another based off of different principles however, are all three are connected by the physics of heat. Let’s start with heat- what exactly is heat? We can understand heat by knowing that “heat is a thermal energy that flows from the warmer areas to the cooler areas, and the thermal energy is the total of all kinetic energies within a given system.” (Soffar, 2015) Now, we can explore the means to which heat is transferred and how each of them occurs. Heat is transferred through conduction at the molecular level and in simple terms, the transfers occurs through physical contact. In conduction, “the substance
In thermodynamics Refrigeration is the major application area, in which the heat is transferred from a lower temperature region to a higher temperature region. The devices which produce refrigeration are known as Refrigerators and the cycle on which it operates are called refrigeration cycles. Vapour compression refrigeration cycle is the most regularly used refrigeration cycle in which the refrigerant is alternately vaporized and condensed and in the vapor phase it is compressed. Gas refrigeration cycle is the well-known refrigeration cycle in which cycle refrigerant remains in the gaseous phase throughout the cycle. Cascade refrigeration are the other refrigeration cycles discussed in this chapter; absorption refrigeration is the one more refrigeration cycle which is used where the refrigerant is dissolved in liquid before it is compressed. One more refrigeration in which refrigeration is produced by passing the electric current through two dissimilar materials is called as the thermoelectric refrigeration.