Thermodynamics Formula Sheet First law of thermodynamics for a system: (Qin - Cout) + (Win - Wout) + (Emass,in - Emass,out) = AU + AKE + APEB Steady Flow Energy Equation (SFEE) for a single stream control volume: Qcv - Wev = m (hz - hy) + (52 20:) + g(zz -zz)) Rates of Conductive & Convectiont Transfer: Qcond = -kcond A ax Qconv = -hconvAAT Rate of Radiative Heat Transfer: Qrad = Azo (TB* - TA* ) where o = 5.67x10-8 W/m2.K4 Entropy balance for a system: at (Ssystem) = Sin - Sout + Sgen where Sinlout = Linjout Tinlout Gibbs equations: TdS = du + PdV = dH - Vdp Gibbs Energy: G =H -TS Boltzmann distribution: s = k In w where k = 1.38x 10-23 J/K For an ideal gas: PV = nRT where R = 8.314 J/(mol.K) and R = - Rspec where an over dot indicates rate and A area K Boltzmann's Cy, cp specific heat constant AU = mcvAT capacity at constant Kcond thermal conductivity V velocity V. P m mass V volume Emass energy associated n number of moles W work with mass transfer PE potential energy Z height above datum KE kinetic energy P pressure e emissivity g gravitational Q heat transfer Stefan Boltzmann constant Rspec gas constant, constant G Gibbs energy Rspec = Cp - CV w number of viable h, H specific enthalpy, s, S specific entropy, arrangements enthalpy, entropy AH = mcpAT time hconv heat transfer temperature coefficient internal energy,Q1 (a) Describe, in words, the three components of the energy in a mass of fluid and their source. [6] (b) State, in words, the first law of thermodynamics for fluid flow through a control volume. [3] (c) i) A hand-dryer, designed for use in public toilets, generates two 250m/s sheets of air at approximately room temperature and at about 35cm above the air intake. The mass flow rate is 42 litres/second and the manufacturers claim it will dry your hands in 12 seconds. Calculate the work done by the dryer to dry your hands. [9] ii) Comment on the value you obtained for the work done to dry your hands relative to the actual energy consumption by the dryer. [2] Assume that the density of air is 1.2 kg/m