PDF Publication Title:
Text from PDF Page: 026
6. Finally, these time derivatives are used to evaluate the new values of the states. Now the temperature and pressure is once again known and the sequence returns to number 2. 5. Thermodynamic theory and modelling In this chapter I will describe the individual components of a gas turbine, the thermodynamic theory of the components and how I have chosen to model them. The models of the compressor, turbine and combustion chamber are originally taken from Perez (2001) and have then been modified. Some of the following figures that describe vital parts of the microturbine, lack axes and are rescaled because of the classified information they contain. 5.1 The compressor equations A centrifugal compressor is designed to increase the pressure of the gas using rotation. It uses mechanical work to rotate the rotor, thus accelerating the gas. After the rotor the gas passes a diffuser, where the increase in cross-section area gives a decrease in velocity and an increase in pressure, according to Bernoulli’s law. The total energy equation below can be found in Cengel (1998). dq −dw −dh −dke −dpe =0 (5.1.1) where dq is the specific external heating, dw is the specific net work, dh is the change in specific enthalpy, dke is the change in kinetic energy and dpe is the change in potential energy. Here the term specific means the amount per unit mass. We can assume that the compressor is adiabatic (i.e. no heat flow in or out) so we can neglect the term dq. We do not have any height differences so the same goes for the term dpe. The velocity does not change very much from the inlet of the compressor to the exit of the diffuser. This small change in kinetic energy can therefore be neglected. This leaves us with: number. The specific heat is defined as the energy required to raise the temperature of a unit mass of a substance by one degree at constant pressure and can be written as: − dw = dh The temperature and therefore the enthalpy increase at compression, resulting in dh as a positive ∂h c p ( T ) = ∂ T After integrating over the compressor we get: p ( 5 . 1 . 3 ) (5.1.4) (5.1.2) − w = ∫ 2 c p (T ) d T 1 where the subscripts 1 and 2 denote the inlet and the outlet respectively. The minus sign in front of w indicates that work is done on the gas from the surroundings, i.e. the compressor. The specific heat can be very accurately calculated with equation (4.4.2), but in this derivation it is enough to use the approximation of constant specific heat. The specific heat for air and water vapor is plotted in figure 14. 22PDF Image | Modelling of Microturbine Systems
PDF Search Title:
Modelling of Microturbine SystemsOriginal File Name Searched:
Model_turbiny_T100.pdfDIY PDF Search: Google It | Yahoo | Bing
Capstone Turbine and Microturbine: Capstone microturbines used and new surplus for sale listing More Info
Consulting and Strategy Services: Need help with Capstone Turbine, sizing systems, applications, or renewable energy strategy, we are here to assist More Info
Container Lumber Dry Kiln: Since 1991 developing and innovating dry kilns using standard shipping containers More Info
Supercritical CO2 Lumber Dry Kiln: Compact fast drying in 3 days or less for small amounts of wood and lumber drying More Info
BitCoin Mining: Bitcoin Mining and Cryptocurrency... More Info
Publications: Capstone Turbine publications for microturbine and distributed energy More Info
FileMaker Software for Renewable Energy Developing database software for the renewable energy industry More Info
CO2 Gas to Liquids On-Demand Production Cart Developing a supercritical CO2 to alcohol on-demand production system (via Nafion reverse fuel cell) More Info
Stranded Gas for low cost power Bitcoin Mining Using stranded gas for generators may provide breakthrough low power costs for cryptocurrency miners. More Info
CONTACT TEL: 608-238-6001 Email: greg@globalmicroturbine.com (Standard Web Page)