Question

An internal combustion engine is running on octane, C8H18 (1) with stoichiometric amount of air. Both the air and fuel enter the engine at room temperature and the exhaust gas leaving the engine contain CO2, CO, H2, N2 and H20. The exhaust temperature is unknown. The brake power is measured and its value is known. It is also estimated that the rate of heat transfer amounts to say, 60% of the brake power; therefore the rate of heat transfer is also a known variable. How would you determine the exhaust temperature? This problem does not require a numerical solution. You need to explain the steps you would follow in a logical sequence to find the exhaust temperature. Please indicate which equations you need to solve at each step. Your answer may look like this (you are free to have your own format as long as it is clear) Step 1: Write down the combustion equation. The known parameters are ......, the unknown parameters are Step 2: Write down .equation. In this equation, the known parameters are ..... , the unknowns are .. Step 4: Calculate .............. from ........... equation in Step 2. Step 5: Use ...........from Step 4, in ..... and find

Answer 1

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Answer :- Given: Fuel Octane Colie BHP- Brack horse Power (noon) Q- Roete of heat transfer - 60% of BHP 10 = 0.6 BHP To = tempt of exhaush gases (Unknown) letts assume, ma = mass flow rate of air ng mass flow rate of Fuel Cpa spectic heat of air Cpg Specific heat of flue gases CV: callocific value of Octane Steps to find out exhaush gas tempt:- - First of all write down combustion eqution C&H + 190 Aca & co & gtha * Now calculate the required amerent of air and mass of flue gases generated.

Page No ☆ Calculate energy available at the Fule. Energy of fuel = mg x C-v & Calculate the enthalpy of cis before Combustion. Har ma. Ca Ta & Calculate enthalpy of exhaust gases after combustion. Hgases = (mating) Cpg Tz & Now apply energy conservation pencople. o and make energy eqution- ng xcov. It malpata = + BHP + (mating) Cpa Tz Heat treens for & Calculate the numerical value of exhaust gas tempt. (1 p. 7) from above egution. Thank You !