Thermodynamics

Abstract

The basic general laws of thermal science are presented and discussed for the application to finite control volume analyses. These are conservation laws for mass, momentum, and energy and a balance law for entropy. Applications to fixed mass systems and to steady flow devices are shown together with the additional special laws governing the behavior of pure substances as equations of state. Further auxiliary laws are indicated as necessary information from the fields of fluid mechanics and heat transfer. Reversible and irreversible processes are discussed, and limitations imposed by the general laws on processes and device behavior are shown. Special attention is given to the possible work that can be extracted from a proposed system or process as the theoretical limit used as a reference for actual systems. The general theory is used to present an ideal heat engine exemplified by a Carnot cycle and relate that to actual heat engines and their efficiencies.

Theoretical Results for Utilizing Nozzle Between the Wind-Way and Wind Turbine in Roof of the Buildings - Wind Speed Increase for Wind Turbine to Produce Electricity

“…Where K, R,T are ratio of special heat, gas constant and temperature respectively [4]. For subsonic wind velocities (M< 1), an increase in area of the nozzle causes wind velocity to reduce but for supersonic wind velocities (M>1), an increase in area causes wind velocity to increase.…”

“…Moreover, the compressibility affects on flow characteristics and the contraction nozzle only increase the velocity of the flow for velocities less than velocity of the sound. 4. Regardless of the calculations of boundary layer in the converging nozzle, we have calculated the velocity of the air at the output of the nozzle.…”

“…According to velocity calculations for incompressible flows, the continuity equation has been utilized [4] to obtain the velocity of the flow in the small diameter of the contraction nozzle (small segment area of the nozzle) or inlet velocity of wind turbine, which is given by: electrical power plants. That is, it is only needed to design suitable blade length for wind turbine corresponds to design of nozzle for increasing the wind speed, afterward, to put the nozzle between the wind-way and wind turbine and then it could be used of the electrical power of the wind turbines more efficiently which can be economically critical for many urban and rural householders.…”

Use of the Molecular-Kinetic Concepts at Introducing the Equation of the First Law of Thermodynamics

“…The FLT equations for "macroscopically stationary body" δQ = dU + δW = dU + p dV, δq = du + pdυ (1) and for flux…”

Numerical study of thermochemical effects on the flowfield structure near the triple point at irregular reflection of shock waves

“…The fluxes through the control volume faces are calculated by the AUSM solver [37] [38,39], which is based on the majorant collision frequency scheme [40]. Energy exchange between the internal and external modes is performed by the Larsen-Borgnakke model [41] using temperature-dependent relaxation numbers. Discrete models are considered for rotational and vibrational modes with the local equilibrium energy redistribution [42].…”