Chapter 6, Problem 6.49P

Argon gas flows through a well-insulated nozzle at steady state. The temperature and velocity at the inlet are 550°R and 150 ft/s, respectively. At the exit, the temperature is 480°R and the pressure is 40 lb/in?. The area of the exit is 0.0085 ft². Use the ideal gas model with k-1.67, and neglect potential energy effects. Determine the velocity at the exit, in ft/s, and the mass flow rate, in lb/s. Step 1 Your answer is correct Determine the velocity at the exit, in ft/s. V₂- 677.088 Hint Step 2 ft/s Determine the mass flow rate, in lb/s, through the nozzle. m = i lb/s Attempts: 2 of 4 used

A rigid tank containing air is subjected to a reversible process in which it is heated from its initial state at T, = 600 K and P, = 1.5 bar to a final state with P, = 4.325 bar. Assuming that air can be modelled as an ideal gas, determine the specific change in entropy As12, (kJ/kg-K). Your Answer:

Equations of State for a gas;P.v = 0.004 (T + 273)U=U0+1,2 Tgiven in the form. In equations P: bar, v: m3/kg, U: kj / kg, t: C. Becomingthe initial volume of a piston cylinder system filled with gas,whose equations are given, is 0, 02m3, its temperature is 90 C, and its pressure is 4 bar. When the gas expands to a lower pressure,the work that the gas does is 3 kJ, and the heat that passes into the environment is 1.9 kJ. What is the final temperature of the gas?

A 60-lb aluminum bar, initially at T3 = 150°F, is placed in a tank together with 190 lb of liquid water, initially at Tw = 70°F, and allowed to achieve thermal equilibrium. The aluminum bar and water can be modeled as incompressible with specific heats c, = 0.216 Btu/lb-°R and Cw = 0.998 Btu/lb-°R, respectively. Consider the aluminum bar and water as the system and ignore heat transfer between the system and its surroundings. Determine the final temperature Tr, in °F, and the amount of entropy produced within the tank, in Btu/°R.

Consider you have an insulated mixing chamber at steady state. This control volume receives two liquid streams at T1 and T2 (with mass flow rates of m1,and m2) and delivers a single stream as an output at T3 and m3.Use the incompressible substance model (with constant specific heat c), neglect the kinetic and potential energy effects, and obtain an expression for T3 in terms of T2, T1 and m1/m3.

In an air conditioning system running at steady-state, m ̇ = 0.7 kg/s of refrigerant 3 134a in saturated liquid state at 48◦C flow through a throttling valve reducing its pressure to a value of p4 = 4 bars. The system is shown in Fig. 1. Then the refrigerant flows through the internal side of a heat exchanger exiting at saturated vapor with p5 = p4. Air enters the external side of the heat exchanger at T1 = 300 K and exits at T2 = 295 K moved by a fan ̇ Figure 1: Problem 1 that consumes WCV = 0.15 kW. Determine the mass flow rate of the air, in kg/s

Argon gas flows through a well-insulated nozzle at steady state. The temperature and velocity at the inlet are 590°R and 150 ft/s, respectively. At the exit, the temperature is 440°R and the pressure is 40 Ibę/in?. The area of the exit is 0.0085 ft². Use the ideal gas model with k = 1.67, and neglect potential energy effects. Determine the velocity at the exit, in ft/s, and the mass flow rate, in Ib/s.

B5

2. An ideal gas undergoes a process from state 1 ( T1= 300 K, P1= 100 kPa) to state 2 ( T2= 600 K, P2 500 kPa). The specific heats of the ideal gas are : c, = 1 kJ/kg-K and c, = 0.7 kJ/kg-K. The change in specific entropy of the ideal gas from state 1 to state 2 (in kJ/kg-K) is (correct to two decimal places).