I mole C I mole CO2 250C.0.1 MPa 25°C,0.MPa Volume I mole CO? ecv=-393,522 KJ, heat is out of control volume Figure C-1: Constant pressure combustion There is no shaft work done in the control volume and the first law for the control volume(SFEE) mass flow of enthalpy in rate of heat addition=mass flow of enthalpy out We can write this statement in the form >, h,+Ocv=>mthe (C.3.1) In Eq(C3. 1)the subscripts"R"and"P"on the summations refer to the reactants(r)and products (P)respectively. The subscripts on the mass flow rates and enthalpies refer to all of the components at inlet and at exit The relation in terms of mass flows can be written in molar form which is often more convenient for reacting flow problems, by using the molecular weight, Mi, to define the molar mass flow rate, ni, and molar enthalpy, hi, for any individual i(or e )component as ni; =m; /M;; mass flow rate in terms of kmoles/sec h i,=M hi; enthalpy per kmole The sfee is. in these terms n:h:+ >nh (C.3.2) The statements that have been made do not necessarily need to be viewed in the context of flow have one unit of C and one unit of O2 at the initial conditions and we carry out a constant pressure reaction at ambient pressure, Pamb. If so, 2C-3C + 02 C02 1 kmole C 1 kmole C02 25o C, 0.1 MPa 25o C, 0.1 MPa Volume 1 kmole C02 Q = -393,522 KJ, heat is out of control volume cv Figure C-1: Constant pressure combustion There is no shaft work done in the control volume and the first law for the control volume (SFEE) reduces to: mass flow of enthalpy in + rate of heat addition = mass flow of enthalpy out. We can write this statement in the form ∑mh + Q ˙ ˙ CV = ∑m he ˙ (C.3.1) ii e R P In Eq. (C.3.1) the subscripts “R” and “P” on the summations refer to the reactants (R) and products (P) respectively. The subscripts on the mass flow rates and enthalpies refer to all of the components at inlet and at exit. The relation in terms of mass flows can be written in molar form, which is often more convenient for reacting flow problems, by using the molecular weight, Mi , to define the molar mass flow rate, n˙i , and molar enthalpy, hi , for any individual ith (or eth) component as n˙i = m˙i / M ; mass flow rate in terms of kmoles/sec i hi = M hi ; enthalpy per kmole i The SFEE is, in these terms, ∑nh + Q ˙ ˙ CV = ∑n he ˙ . (C.3.2) ii e R P The statements that have been made do not necessarily need to be viewed in the context of flow processes. Suppose we have one unit of C and one unit of O2 at the initial conditions and we carry out a constant pressure reaction at ambient pressure, Pamb . If so, 2C-3