IndexIntroductionLiterature reviewClemente and Desormes methodResults and discussionHeat capacity at constant volume and pressureHeat transfer coefficientConclusionThe isentropic exponent, which is the ratio between the heats specific constant pressure and constant volume respectively has various applications in the industry. The objective of this laboratory was to determine the isentropic coefficient of air. This was achieved by taking pressure difference measurements from the laboratory and using the Clement and Desormes method to calculate the isentropic coefficient. The next objective was to estimate the heat transfer coefficient responsible for the resulting heat transfer between the air and the vessel walls. Furthermore, it was necessary to decide which process was better between the quick release valve and the slow release valve. The pressure difference was recorded every minute until stabilization was achieved, before and after performing the valve release, for both fast and slow releases. The isentropic exponent was then calculated for each method and compared to the theoretical isentropic exponent of 1.4 at 298K. The average isentropic exponents for slow and fast release were determined to be 1.22 and 1.21 with deviations from the theoretical value of 13.76% and 12.74%, respectively. Microsoft Excel solver was used to determine the heat transfer coefficient as 1.55 W/m2 K and 1.59 W/m2 K for fast and slow release respectively. The rapid release process was deemed the best as it had a lower deviation of the isentropic exponent from the theoretical isentropic exponent. Air Cp and Cv values ​​were determined to be 46.41 J/mol K and 38.10 J/mol K respectively for fast release, slow release Cv and Cp values ​​were determined to be 40.12 J/ mol K and 51, 36 J /mol K. Say no to plagiarism. Get a tailor-made essay on "Why Violent Video Games Shouldn't Be Banned"? Get Original Essay IntroductionThe isentropic exponent is the ratio of isobaric heat capacity (Cp) to isochoric heat capacity (Cv). According to the theory in question, for an ideal gas that is diatomic like air, the isentropic exponent is equal to 1, 4. The purpose of the experiment is to use the experimental data obtained to determine the isentropic exponent of air using the method of Clement and Desormes and compare it with the theoretical value, having as a secondary aim that of determining Cp and Cv of the air, the heat exchange coefficient due to the heat exchange that occurs between the air and the walls of the container, and which , between the fast and slow release of air into the vessel, is the most efficient.Literature ReviewA polytropic process, a process in which work is done on or by the gas, defines the process that occurs during compression and expansion of a gas and obeys the following law: Where n is the polytropic index. The value of n depends on the process conditions (i.e. isothermal, adiabatic, etc.). This report examines the process conducted under isentropic conditions, defined as a reversible adiabatic process, so when the process is isentropic and the gas is ideal, the gamma is used instead of the letter n. The new equation called Poisson's law is as follows. Where gamma is the isentropic exponent. The isentropic exponent is defined as the ratio of the heat capacity at constant pressure to constant volume, which gives the approximate value of 1.4 for an ideal, diatomic gas such as air. Clemente and Desormes Method A successful application of this method requires a list of assumptions to be made. Thesehypotheses included the following: Air behaves like an ideal gas. The specific heats, Cp and Cv do not vary with temperature. The expansion of the gas is adiabatic after a rapid release The temperature in the laboratory remains constant throughout the duration of the experiment The heat transfer coefficient is constant over the entire surface of the container. The determination of the isentropic exponent by the Clement-Desormes method is described by two important steps described below: The first step involves the adiabatic compression of a gas in a closed container. A pump is used to pressurize the air contained in the vessel resulting in a change in temperature and an increase in pressure above the atmosphere. As soon as the pump is released the system cools isochorously and after a certain time the conditions inside the vessel tend to atmospheric ones. Heat transfer occurs from the air to the walls of the tank since the temperature of the walls is assumed to be equal to the ambient temperature. The pressure is reduced by quickly opening a release valve. The gas temperature drops to ambient conditions. Isochoric heating occurs and the walls heat the air, heat transfer occurs from the walls to the air. This is achieved by performing a slow release (slowly opening and closing the valve) once the vessel has stabilized from the previous pressurization. At equilibrium of both processes, the head is recorded and used to determine the isentropic exponent. Poisson's law is then used to determine the experimental value of gamma for air. During isochoric heating and cooling of the gas, a convective heat transfer occurs between the gas and the gas walls. Results and discussion For each method (fast-release and slow-release), 5 trials with different pumping amounts were conducted to estimate the isentropic exponents based on the different gauge heights measured. The isentropic exponent ϒ for each consecutive stroke for both fast and slow release is plotted and found to be different from the theoretical isentropic exponent of 1. 4. Taking gauge height difference readings for both expansion and compression, the average isentropic exponents for both cases are 1.22 and 1.21 respectively with an error of 12.54% and 13.76% compared to the isentropic exponent of 1.4 obtained at 298K. This can be explained by human error since the pressure variation is very small in the considered time interval. Other factors that contributed to the variation in the value of the isentropic coefficient could be that the pumped air was a mixture of gases with variable composition in different regions. Heat capacity at constant volume and pressure From our thermodynamics book, we learned that Cp and Cv are constant, the Cp and Cv values ​​for air are 1.005 kJ/kg K and 0.718 kJ/kg K respectively. The Cp and Cv values Cv were calculated for each experimental run for both the fast-release and slow-release methods. The respective mean values ​​for both methods show that the specific heats for the slow release were higher than for the fast release method. When a gas is heated to a constant volume, the heat energy supplied increases the temperature and therefore the internal energy of the gas because the gas cannot expand further beyond the containment of the constant volume in which it is held. The heat capacity of the liquid is a function of temperature, pressure has a slight effect on Cv unless working at high pressure. In our system the increase in pressure means increase in temperature, they have a directly proportional relationship therefore increase in Cv. The values.