6-1 A 1956 technical report describes the supersonic wind tunnel (E-l) of the Gas Dynamics Facility of the Arnold Engineering Development Center, Tullahoma, Tennessee. The control station is shown in the figure. The report identifies the test section inlet as a 6 inch diameter pipe that can deliver a mass flow rate of 190 lbm/sec at air pressure and temperature of 4 atmospheres and 100F respectively. a) Based on this information find the velocity of the air in the test inlet sectionA: V = 3416 ft/sec

b) Calculate the rate of flow energyA: 38.4 Btu/sec

c) Find the rate of energy transport by massA: 69.8103 Btu/sec

d) Find the error in c) if the kinetic energy term is ignored. A: 63%6-2The performance of the compressor section of the T53-L-13B turboshaft engine is as shown:Pressure ratio7.2:1

Inlet temperature (SLS)59F

Exit Temperature530F

Airflow10.7 lbm/sec

a) Determine the work done by the compressor in kJ/kgA: 1292kW

b) The power required to drive the compressor if it is 87% efficientA: 1485kW

6-3 As the plant design engineer, you want to use a throttling valve to create saturated vapor (x=1) from a supply source consisting of a saturated mixture with a steam quality of 96% at 1200psia using a Copeland CV series steam throttling valve shown. a) At what pressure do you achieve your objective? A: ~1,600 psia

7-1 W. Brandstetter and R. Dziggel of VW Wolfsburg Ag. report in SAE technical paper # 820441 (1982) that the VW 4 cylinder turbocharged engine has the performance characteristics shown in their Fig. 35. (bsfc is brake specifc fuel consumption; a measure of fuel flow rate in grams per hour divided by power in kW; RB is a measure of exhaust opacity)

The Hydrogen Analysis Resource Center of the US Department of Energy provides the below information relating to fuel energy content: Liquid FuelsBtu/gal [2]Btu/lb [3]MJ/kg [4]

Crude oil129,67018,35242.686

Conventional gasoline116,09018,67943.448

Reformulated or low-sulfur gasoline113,60218,21142.358

CA reformulated gasoline113,92718,27242.500

U.S. conventional diesel128,45018,39742.791

Low-sulfur diesel129,48818,32042.612

Petroleum naphtha116,92019,32044.938

NG-based FT naphtha111,52019,08144.383

Residual oil140,35316,96839.466

Methanol57,2508,63920.094

Ethanol76,33011,58726.952

Butanol99,83714,77534.366

Acetone83,12712,72129.589

a) Based on the information provided calculate the thermal efficiency of the engine using low-sulfur diesel fuel. A: 26%b) From energy balance, how much energy is rejected to the environment? A: 145 kJ/sec7-2The Wheelabrator waste to energy facility in Lisbon CT produces electrical energy from recycled municipal solid waste (MSW) under the auspices of the Connecticut Resource Recovery Agency. The company claims that it processes up to 500 tons per day of municipal solid waste with a generating capacity of 15,000 kilowatts of electrical energy, or the equivalent of supplying the electrical needs of 18,000 Connecticut homes. Tchobanoglous et al (Tchobanoglous, G., Theisen, H., and Vigil, S. (1993) Integrated Solid Waste Management, Chapter 4, McGraw-Hill, New York.) reports that the average energy content of the MSW feedstock in New York City is 12,332 MJ/ton. a) What is the thermal efficiency of the Wheelabrator plant based on this information?A: 21%

7-3Using the published technical information shown below for the TempStar model N4A318AKA: a) What is the COP? A: 1.88b) What is the EER? A: 6.41EER rating is performed for an outside air temperature of 95F and inside temperature of 80F. Based on these temperatures:c) What is COPcarnot? A: 36.0d) Whats is EER carnot? A: 122.8

7-4As the Heating and Cooling contractor, you have estimated that a new construction residential dwelling loses heat at a rate proportional to the difference between the inside and outside temperature as follows:Qdot = 500 T where:Qdot = heat loss to outside (Btu/hr)T = Temperature difference between inside and outside (F)

You will use the Goodman GSZ130361B heat pump to maintain a temperature of 70F inside and will augment the heat pump with a gas-fired furnace when conditions require. Based on the below performance characteristics: a) At what temperature will the gas-fired furnace need to kick on? A: ~25Fb) What will be the power required to heat the house when the outside temperature is 50F if the COP is as indicated below?A: 0.816 kW