91Ó°ÊÓ

Air flows in a horizontal duct at \(20^{\circ} \mathrm{C}\) with a velocity of \(180 \mathrm{~m} / \mathrm{s}\). If the velocity increases to \(250 \mathrm{~m} / \mathrm{s}\), determine the corresponding temperature of the air. Hint: Use the energy equation to find \(\Delta h\).

The converging-diverging nozzle at the end of a supersonic jet engine is to be designed to operate efficiently when the absolute outside air pressure is \(25 \mathrm{kPa}\). If the absolute stagnation pressure within the engine is \(400 \mathrm{kPa}\) and the stagnation temperature is \(1200 \mathrm{~K},\) determine the exit plane diameter and the throat diameter for the nozzle if the mass flow is \(15 \mathrm{~kg} / \mathrm{s}\). Take \(k=1.40\) and \(R=256 \mathrm{~J} / \mathrm{kg} \cdot \mathrm{K}\).

Air flows at \(200 \mathrm{~m} / \mathrm{s}\) through the pipe. Determine the Mach number of the flow and the mass flow if the temperature is \(500 \mathrm{~K}\) and the absolute stagnation pressure is \(200 \mathrm{kPa}\). Assume isentropic flow.

Air flows at \(200 \mathrm{~m} / \mathrm{s}\) through the pipe. Determine the pressure within the flow if the temperature is \(400 \mathrm{~K}\) and the absolute stagnation pressure is \(280 \mathrm{kPa}\). Assume isentropic flow.

The tank contains oxygen at a temperature of \(70^{\circ} \mathrm{C}\) and absolute pressure of \(800 \mathrm{kPa}\). If the converging nozzle at the exit has a diameter of \(6 \mathrm{~mm}\), determine the initial mass flow out of the tank if the outside absolute pressure is \(100 \mathrm{kPa}\).