1. ME 475/675 Introduction to Combustion Lecture 9

2. Announcements Midterm 1 September 29, 2014 (two weeks from today) HW 3 Ch 2 (57), Due now HW 4 Due Monday, September 22, 2014 Ch 2 (33, 35, 47, 50, 54, 63) I’m rethinking the Example/Homework assignments…

3. Computer Programs Provided by Book Publisher Described in Appendix F For “complex” reactions (11 product species) Fuel: C N H M O L N K Oxidizer: Air Download from web: www.mhhe.com/turns3ewww.mhhe.com/turns3e student edition Computer codes Access to TPEquil, HFFlame, UVFlame Extract All TPEQUIL (TP Equilibrium) Use to find Equilibrium composition and mixture properties Required input Fuel C N H M O L N K Temperature Pressure Equivalence ratio (with air) to determine initial number of moles of each atom

4. HPFLAME (H P Flame) Use to find Adiabatic flame temperature for constant pressure Required Input Fuel, equivalence ratio, enthalpy of reactants H R, pressure For constant pressure: H P = H R Find T Ad In our examples we assume ideal combustion so we knew the product composition But this program calculates the more realistic equilibrium composition of the products from a (complex) equilibrium calculation (multiple equilibrium reactions) But this requires T Prod = T Ad, which we are trying to find! Requires program (not humans) to iterate

5. Example 2.8, Page 54 A recuperator (heat exchanger) is employed in a natural-gas-fired heat-treating furnace. The furnace operates at atmospheric pressure with an equivalence ratio of 0.9. The fuel gas enters the burner at 298 K, and the air is preheated. (a) Determine the effect of air preheat on the adiabatic temperature of the flame zone for a range of inlet air temperatures from 298 to 1000 K. (b) What fuel savings results from preheating the air from 298 to 600 K? Assume that the temperature of the flue gases at the furnace exit, prior to entering the recuperator, is 1700 K, both with and without air preheat.