Recent content by dboozer

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    How do I turn on model physics in MCNP6 to solve a fatal error?

    I haven't tried to run your code, but one thing that may be helpful is to specify which cross section libraries you want to use. You'll need to consult the manual to see which ones match your problem best, but you'll probably be fine in using .80c. So for each ZAID, try this: for Hydrogen...
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    Calculating Temperature of Fuel-Air Mixture

    A friend helped me out earlier... The fuel-air mixture is traveling through the inlet manifold toward the engine. The inlet manifold is heated so as to vaporize the fuel. Assuming an equivalence ratio of 0.8 and a stoichiometric A/F of 14.4, one can calculate the mass of the fuel mixed with...
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    Calculating Temperature of Fuel-Air Mixture

    No one has any input or ideas? Surely there's someone who can help me!
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    Calculating Temperature of Fuel-Air Mixture

    Since \dot{Q}_{air}=c_p \dot{m}_a \Delta T=c_p m_a \Delta T (\frac{N}{2}), You can calculate the change in temperature of the air to be \Delta T = 46.62 C and thus the final temperature of the air is 86.62 C. The problem says you can neglect the effects of the heat capacity of the liquid...
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    Calculating Temperature of Fuel-Air Mixture

    The mass of air inducted into the cylinders is 0.85(1.06 kg/m^3)(1.6 L)(1 m^3/1000 L)(1000 g/kg) = 1.44 g
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    Calculating Temperature of Fuel-Air Mixture

    Homework Statement In many spark-ignition engines, liquid fuel is added to the inlet air upstream of the inlet manifold above the throttle. The inlet manifold is heated to ensure that under steady-state conditions the fuel is vaporized before the mixture enters the cylinder. At normal...
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    How Do Engine Parameters Affect Performance at 2500 RPM?

    I think I got most of it... by looking at a valve timing diagram, I should be able to use the rpm to get an idea of how each process is. This will answer parts c and d. I think I can use the diagram to answer e and f, but I'm not 100% sure on that...
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    How Do Engine Parameters Affect Performance at 2500 RPM?

    It makes sense that the faster the piston moves down, the faster the air is drawn into the chamber. Assuming a constant density, v_1=v_2 \frac{A_2}{A_1}= \frac{10.796 m/s}{20\%}=53.98 m/s
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    How Do Engine Parameters Affect Performance at 2500 RPM?

    Homework Statement Several velocities, time, and length scales are useful in understanding what goes on inside engines. Make estimates of the following quantities for a 1.6-liter displacement four-cylinder spark-ignition engine, operating at wide-open throttle at 2500 rev/min. a. The mean...
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    Given certain parameters, find the percentage of energy that becomes

    Since the combustion efficiency is 0.94 and the energy content of the fuel entering the engine is 190kW, 6% of this energy (11.4 kW) is lost as exhaust chemical energy. This means that 178.6 kW of fuel energy is delivered to the engine per cycle. Of this 178.6 kW, 60 kW are lost to the coolant...
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    Given certain parameters, find the percentage of energy that becomes

    Thanks for the help gsal. Your post gave me some ideas, especially the bit about the energy left in the unburned fuel... I'm amazed something as simple as energy balance escaped me. I looked up some definitions to see if they'd help. Mechanical Efficiency: Ratio of useful power delivered...
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    Given certain parameters, find the percentage of energy that becomes

    Homework Statement The brake fuel conversion efficiency of an egine is 0.3. The mechanical efficiency is 0.8. The combustion efficiency is 0.94. The heat losses to the coolant and oil are 60 kW. The fuel chemical energy entering the engine per unit time, (m_f * Q_HV), is 190 kW. What...
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