- #1
gezibash
- 24
- 0
Recently I have been studying thermodynamics and I wanted to analyze a fictitious car piston of my own design. Indeed I have quite some questions, but the most important is this one, and maybe someone could give me an opinion on my progress.
I started off by selecting the fuel, which according to some internet source (I forgot, can't cite) suggested that I should use Octane, so I wrote the chemical equation,
C_8H_{18} + 12.5(O_2+3.76N_2) \rightarrow 8CO_2 + 9H_2O + 23.5N_2
and I used the AFR ultimately computing the ratio to be,
i = \frac{m_o}{m_f} = 15.0279
After this, I computed the densities of air and octane,
\rho_A = 1.2754 \frac{\text{kg}}{\text{m}^3}
and
\rho_F = 703 \frac{\text{kg}}{\text{m}^3}
I randomly selected a Vp = 1.8L volume, so I went ahead and wrote these two equations,
<br /> m_A = i \cdot m_F \\<br /> \frac{1}{\rho_A}m_A + \frac{1}{\rho_F}m_F = V_p<br />
From which, when you solve it, you get a total mass of
<br /> m_T = m_A + m_F = 2.448 \; \text{grams}<br />
My question is, is this feasible? Does the entire mass of the fuel and air mixture amount to about 2.448 grams in a single cylinder? If not, where did I go wrong?
Also, I would be most grateful if someone could point to a book or anything of the educational nature on this subject?
My next steps from here would be to try and figure the heat of combustion and then I will start to compute an Otto Cycle, perhaps later even use a more realistic intake/exhaust cycle.
I started off by selecting the fuel, which according to some internet source (I forgot, can't cite) suggested that I should use Octane, so I wrote the chemical equation,
C_8H_{18} + 12.5(O_2+3.76N_2) \rightarrow 8CO_2 + 9H_2O + 23.5N_2
and I used the AFR ultimately computing the ratio to be,
i = \frac{m_o}{m_f} = 15.0279
After this, I computed the densities of air and octane,
\rho_A = 1.2754 \frac{\text{kg}}{\text{m}^3}
and
\rho_F = 703 \frac{\text{kg}}{\text{m}^3}
I randomly selected a Vp = 1.8L volume, so I went ahead and wrote these two equations,
<br /> m_A = i \cdot m_F \\<br /> \frac{1}{\rho_A}m_A + \frac{1}{\rho_F}m_F = V_p<br />
From which, when you solve it, you get a total mass of
<br /> m_T = m_A + m_F = 2.448 \; \text{grams}<br />
My question is, is this feasible? Does the entire mass of the fuel and air mixture amount to about 2.448 grams in a single cylinder? If not, where did I go wrong?
Also, I would be most grateful if someone could point to a book or anything of the educational nature on this subject?
My next steps from here would be to try and figure the heat of combustion and then I will start to compute an Otto Cycle, perhaps later even use a more realistic intake/exhaust cycle.
