An air-standard Diesel cycle has a compression ratio of 16 and a cutoff ratio of 2. At the beginning of the compression process, air is at 95 kPa and $27^{\circ} \mathrm{C}$. Accounting for the variation of specific heats with temperature, determine (a) the temperature after the heat-addition process, (b) the thermal efficiency, and (c) the mean effective pressure.

A simple Brayton cycle using air as the working fluid has a pressure ratio of 10. The minimum and maximum temperatures in the cycle are 295 and 1240 K. Assuming an isentropic efficiency of 83 percent for the compressor and 87 percent for the turbine, determine (a) the air temperature at the turbine exit, (b) the net work output, and (c) the thermal efficiency.

For comparison of Diesel- and Otto-engine cycles: (a) Show that the thermal efficiency of the air-standard Diesel cycle can be expressed as $\eta=1-\left(\frac{1}{r}\right)^{\gamma-1} \frac{r_{c}^{\gamma}-1}{\gamma\left(r_{c}-1\right)}$ where r is the compression ratio and $r_c$ is the cutoff ratio, defined a $r_{c}=V_{A} / V_{D}.$ (b) Show that for the same compression ratio the thermal efficiency of the air-standard Otto engine is greater than the thermal efficiency of the air-standard Diesel cycle. (c) If $\gamma=1.4,$ how does the thermal efficiency of an air-standard Otto cycle with a compression ratio of 8 compare with the thermal efficiency of an air-standard Diesel cycle with the same compression ratio and a cutoff ratio of 2? How is the comparison changed if the cutoff ratio is 3?

An ideal diesel engine has a compression ratio of 20 and uses air as the working fluid. The state of air at the beginning of the compression process is 95 kPa and $20^\circ C.$ If the maximum temperature in the cycle is not to exceed 2200 K, determine (a) the thermal efficiency and (b) the mean effective pressure. Assume constant specific heats for air at room temperature.

An air-standard Diesel cycle has a compression ratio of 18.2 . Air is at 120 degree F and 14.7 psia at the beginning of the compression process and at 3200R at the end of the heat-addition process. Accounting for the variation of specific heats with temperature, determine

(a) the cutoff ratio,

(b) the heat rejection per unit mass, and

(c) the thermal efficiency.

A simple ideal Brayton cycle with air as the working fluid has a pressure ratio of 10. The air enters the compressor at 520 R and the turbine at 2000 R. Accounting for the variation of specific heats with temperature, determine (a) the air temperature at the compressor exit, (b) the back work ratio, and (c) the thermal efficiency.

An air-standard Diesel cycle has a compression ratio of 18.2. Air is at $120^{\circ} \mathrm{F}$ and 14.7 psia at the beginning of the compression process and at 3200 R at the end of the heat-addition process. Determine the exergy destruction associated with the heat rejection process of the cycle, assuming a source temperature of 3200 R and a sink temperature of 540 R. Also, determine the exergy at the end of the isentropic expansion process. Account for the variation of specific heats with temperature.

At the beginning of a recent year, The Walt Disney Company's liabilities equaled $49,637 million. During the year, assets increased by$2.809 million, and year-end assets equaled $98.598 million. Liabilities decreased$4,944 million during the year. What were its beginning and ending amounts for equity? (Hint: Apply the accounting equation.)

An air-standard Diesel cycle has a compression ratio of $18.2$. Air is at $47^{\circ} \mathrm{C}$ and $100 \mathrm{~kPa}$ at the beginning of the compression process and at $1800 \mathrm{~K}$ at the end of the heat-addition process. Accounting for the variation of specific heats with temperature, determine $(a)$ the cutoff ratio, (b) the heat rejection per unit mass, and $(c)$ the thermal efficiency.

What is the second-law efficiency? How does it differ from the first-law efficiency?

A simple ideal Brayton cycle operates with air with minimum and maximum temperatures of $27^{\circ} \mathrm{C}$ and $727^{\circ} \mathrm{C}.$ It is designed so that the maximum cycle pressure is 2000 kPa and the minimum cycle pressure is 100 kPa. Determine the net work produced per unit mass of air each time this cycle is executed and the cycle's thermal efficiency. Use constant specific heats at room temperature.

A simple ideal Brayton cycle operates with air with minimum and maximum temperatures of 27 degree C and 727 degree C. It is designed so that the maximum cycle pressure is 2000kPa and the minimum cycle pressure is 100kPa. Determine the net work produced per unit mass of air each time this cycle is executed and the cycle's thermal efficiency. Use constant specific heats at room temperature.

For fixed maximum and minimum temperatures, what is the effect of the pressure ratio on (a) the thermal efficiency and (b) the net work output of a simple ideal Brayton cycle?

A four-cylinder two-stroke 2.4-L diesel engine that operates on an ideal Diesel cycle has a compression ratio of 22 and a cutoff ratio of 1.8. Air is at $70^\circ C$ and 97 kPa at the beginning of the compression process. Using the cold-air- standard assumptions, determine how much power the engine will deliver at 3500 rpm.