Table of contentsIntroductionLiterature reviewClément and Desormes methodResults and discussionHeat capacities at constant volume and pressureHeat transfer coefficientConclusionThe Isentropic exponent, which is the ratio of specific heats at constant pressure and constant volume respectively has various applications in industry. The objective of this laboratory was to determine the isentropic coefficient of air. This was achieved by taking pressure difference measurements in the laboratory and using the Clément 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. Additionally, it was necessary to decide which process was better between a quick release valve and a slow release valve. The pressure difference was recorded every minute until stabilization was reached before and after a valve release, for both fast and slow release. 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 found to be the best because it had a smaller 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 should not be banned”?Get original essayIntroductionThe isentropic exponent is the ratio of isobaric heat capacity (Cp) to isochoric heat capacity (Cv). According to the relevant theory, for a diatomic ideal gas like air, the isentropic exponent is equal to 1.4. The aim of the experiment is to use the experimental data obtained to determine the isentropic exponent of air using the Clément and Desormes method. and compare this to the theoretical value, the secondary goal being to determine Cp and Cv of the air, the heat transfer coefficient due to the heat transfer which takes place between the air and the walls of the tank, and which, between the fast and slow release of air into the tank, is the most efficient. Literature reviewA polytropic process, a process where work is done on or by the gas, defines the process that takes place during compression and of the expansion of a gas, and it 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 carried out under isentropic conditions, defined as a reversible adiabatic process. So when the process is isentropic and the gas is ideal, 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 heat capacity at constant pressure and constant volume, which gives the approximate value of 1.4 for an ideal, diatomic gas like air. Clément and Desormes Method A successful application of this method requires a listassumptions to make. These hypotheses were as follows: 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 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 The determination of the isentropic exponent according to the Clément-Desormes method is described by two important steps which are described below: The first step involves the adiabatic compression of a gas in a closed container. A pump is used to pressurize the air in the container, causing the temperature to change and the pressure to increase above atmospheric pressure. As soon as the pump is released, the system cools isochorically and after a while the conditions inside the vessel tend towards atmosphere. Heat transfer occurs from the air to the walls of the tank because the wall temperature is assumed to be at room temperature. The pressure is reduced by quickly opening a relief valve. The gas temperature drops to ambient conditions. Isochoric heating occurs and the walls warm 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 container has stabilized following pre-pressurization. At equilibrium of the two processes, the head of charge is recorded and used to determine the isentropic exponent. Poisson's law is then used to determine the experimental gamma value for air. During isochoric heating and cooling of gas, convective heat transfer occurs between the gas and the gas walls. Results and discussion For each method (quick-release and slow-release), 5 tests with different pumping amounts were performed to estimate the isentropic exponents based on the different gauge heights measured. The isentropic exponent ϒ for each consecutive pass for fast and slow release is shown and found to be different from the theoretical isentropic exponent of 1. 4. Taking the pressure gauge height difference readings for 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 may be due to human error as the pressure change is very small in the time interval taken. 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 whose composition varies depending on the region. Heat capacities at constant volume and pressure From our thermodynamics book we learned that Cp and Cv are constants, the Cp and Cv values ​​for air at are 1.005 kJ/kg K and 0.718 kJ/kg respectively K. Cp and Cv values ​​were calculated for each experimental run for the fast or slow release method. The respective average values ​​for the two methods show that the specific heats for the slow release were greater than for the rapid release method. When a gas is heated to a constant volume, the thermal energy supplied increases the temperature and therefore the internal energy of the gas, because the gas can no longer expand beyond the constant volume in which it is kept. The heat capacity of a liquid is a function of the temperature, the pressure has a slight effect on the Cv unless we work at high pressure. In our system the increase in pressure means the increase in temperature, they have a.