Thermodynamics Equations Contents:Fluid PropertiesPressurePure SubstancesFirst LawWorkInternal EnergyEnthalpyPowerConservation of MassTransient Flow ProcessThermal EfficiencyHeat EnginesEntropyEntropy AnalysisDevice EfficiencyMixturesAir MixturesCombustion Fluid Properties \nu=\dfrac{V}{m}P=\dfrac{F}{A} \rho=\dfrac{m}{V}=\dfrac{1}{\nu} Pressure P_fA=P_0A+mgP_f=P_0+\sum_0^n\rho_iz_ig P_f=P_0+\rho_fzg Pure Substances \nu_{fg}=\nu_g-\nu_f\nu(T)\approx\nu_f(T)\nu=x\nu_{fg}+\nu_fR=\dfrac{\overline{R}}{M} \displaystyle x=\dfrac{m_g}{m}\displaystyle \nu=(1-x)\nu_f+x\nu_g\displaystyle PV=n\overline{R}T\displaystyle P\nu=RT PhasePT \nu Compressed LiquidP>P_{sat}T < T_{sat} \nu < \nu_f Saturated MixtureP=P_{sat}T=T_{sat} \nu_f < \nu < \nu_g Superheated VapourP < P_{sat}T>T_{sat} \nu>\nu_g First Law Q=\Delta U+\Delta KE+\Delta PE+W\Delta KE=\frac{1}{2}\sum m_ev^2_e-\frac{1}{2}\sum m_iv^2_i Q=\Delta H+\Delta KE+\Delta PE+W\Delta PE=\sum m_egz_e-\sum m_igz_i Work \displaystyle W=\int_{V_1}^{V_2}PdVPV^n=C \displaystyle w=\dfrac{W}{m}\displaystyle\displaystyle Internal Energy \displaystyle U=mu\Delta u=C_{v 0}\Delta T \displaystyle \Delta U=\sum m_eu_e-\sum m_iu_i Enthalpy H=mhh=u+P\nu\Delta h=C_{p0}\Delta T \displaystyle H=U+PV\displaystyle \Delta H=\sum m_eh_e-\sum m_ih_i Power \dot{W}=\dfrac{dW}{dt}\displaystyle\dot{Q}-\dot{W}=\sum\dot{m}_e\left(h_e+\dfrac{v^2_e}{2}+gz_e\right)-\sum\dot{m}_i\left(h_i+\dfrac{v^2_i}{2}+gz_i\right) \dot{Q}=\dfrac{dQ}{dt} Conservation of Mass \displaystyle\sum\dot{m}_i=\sum\dot{m}_e Transient Flow Process \displaystyle Q_{cv}-W_{cv}=\sum m_e\left(h_e+\dfrac{v^2_e}{2}+gz_e\right)-\sum m_i\left(h_i+\dfrac{v^2_i}{2}+gz_i\right)+m_2\left(u_2+\dfrac{v^2_2}{2}+gz_2\right)-m_1\left(u_1+\dfrac{v^2_1}{2}+gz_1\right) Thermal Efficiency \displaystyle\eta=\dfrac{\dot{W}_{net}}{\dot{Q}_{in}}\displaystyle\beta^\prime=\dfrac{\dot{Q}_{heating}}{\dot{W}_{compressor}} \displaystyle\beta=\dfrac{\dot{Q}_{cooling}}{\dot{W}_{compressor}} Heat Engines W=Q_H-Q_L\eta=\dfrac{W}{Q_H}=\dfrac{T_H-T_L}{T_H}\beta^\prime=\dfrac{Q_H}{W}=\dfrac{T_H}{T_H-T_L} \left(\dfrac{Q_H}{Q_L}\right)_{rev}=\dfrac{T_H}{T_L}\beta=\dfrac{Q_L}{W}=\dfrac{T_L}{T_H-T_L} Entropy \displaystyle\oint\dfrac{\delta Q}{T}=\dfrac{Q_H}{T_H}-\dfrac{Q_L,irr}{T_L}<0s=\dfrac{S}{m}TdS=dU+PdVs_2-s_1=C\ln\left(\dfrac{T_2}{T_1}\right)s_2-s_1=C_{v 0}\ln\left(\dfrac{T_2}{T_1}\right)+R\ln\left(\dfrac{\nu_2}{\nu_1}\right)S_{gen}=m_{c.m.}(s_2-s_1)_{c.m.}-\dfrac{Q_{1\to 2}}{T_{surr}} \displaystyle S_2-S_1=\int_1^2\left(\dfrac{\delta Q}{T}\right)_{rev}\displaystyle Q_{1\to 2}=\int_1^2 TdSTdS=dH-VdPs=s_f+xs_{fg}s_2-s_1=C_{p 0}\ln\left(\dfrac{T_2}{T_1}\right)-R\ln\left(\dfrac{P_2}{P_1}\right) Entropy Analysis \displaystyle S_{1\to 2}=(m_2s_2-m_1s_1)_{cv}+\sum m_es_e-\sum m_is_i-\dfrac{Q_{1\to 2}}{T_{surr}} \displaystyle w_{ideal}=\dfrac{1}{2}(v^2_i-v^2_e)+g(z_i-z_e)-\int_i^e\nu dP Device Efficiency \displaystyle \eta_T=\dfrac{w_T}{w_{T,s}}=\dfrac{h_i-h_e}{h_i-h_{e,s}}\displaystyle \eta_N=\dfrac{v^2_e}{v^2_{e,s}} \displaystyle \eta_{P/C}=\dfrac{w_{P/C,s}}{w_{P/C}}=\dfrac{h_i-h_{e,s}}{h_i-h_e} Mixtures \displaystyle c_i=\dfrac{m_i}{m_{tot}}\displaystyle y_i=\dfrac{n_i}{n_{tot}}R_{tot}=\sum_{i=1}^k c_iR_iM_{tot}=\left[\sum_{i=1}^k\dfrac{c_i}{M_i}\right]^{-1}u=\sum_{i=1}^k c_iu_iC_{v 0,tot}=\sum_{i=1}^k c_iC_{v 0,i}s_2-s_1=\ln\left(\dfrac{T_2}{T_1}\right)\sum_{i=1}^k c_iC_{p0,i}-\ln\left(\dfrac{P_2}{P_1}\right)\sum_{i=1}^k c_iR_i \displaystyle \sum_{i=1}^k c_i=1\displaystyle \sum_{i=1}^k y_i=1M_{tot}=\dfrac{m_{tot}}{n_{tot}}P_i=y_iPh=\sum_{i=1}^k c_ih_iC_{p0,tot}=\sum_{i=1}^k c_iC_{p0,i} Air Mixtures \displaystyle P=P_a+P_v\displaystyle \phi=\dfrac{m_v}{m_g}=\dfrac{P_v}{P_g}h=C_{p0,a}T+\omega h_v\dot{V}_{tot}=\dfrac{\dot{m}_{tot}}{\rho_{tot}} \displaystyle \omega=0.622\dfrac{P_v}{P_a}\displaystyle u=C_{v 0,a}T+\omega u_v\dot{m}_{tot}=\dot{m}_a(1+\omega)\omega_1=\dfrac{C_{p0,a}(T_2-T_1)+\omega_2h_{fg,2}}{h_{g,1}-h_{f,2}} Combustion C_xH_y+a(O_2+3.76N_2)\to bCO_2+cH_2O+3.76aN_2\displaystyle AF_{mass}=\dfrac{m_{air}}{m_{fuel}}\displaystyle AF_{mass}=AF_{mol}\dfrac{M_{air}}{M_{fuel}}H_R=\sum_Rn_i\overline{h}_i\overline{h}_{T,P}=\overline{h}^0_f+\Delta\overline{h}_{T,P}\displaystyle U_{RP}=\sum_Pn_e(\bar{h}_f^0+\Delta\bar{h}-P\bar{\nu})_e-\sum_Rn_i(\bar{h}_f^0+\Delta\bar{h}-P\bar{\nu})_i \displaystyle n_{air}=4.76(x+0.25y)\displaystyle AF_{mol}=\dfrac{n_{air}}{n_{fuel}}Q+H_R=H_PH_P=\sum_Pn_e\overline{h}_e\displaystyle H_{RP}=\sum_Pn_e(\bar{h}_f^0+\Delta\bar{h})_e-\sum_Rn_i(\bar{h}_f^0+\Delta\bar{h})_i