If the heat loss by radiation in 3-24 can not be neglected and the surface emissivity is 0.8, what will be the surface temperature?  Note 1: you can assume that equation 3-10 is valid in describing the radiation heat loss.  Note 2: If model correctly, you will end up with a fourth order algebraic equation.  You should try to solve it using trials and errors method.  Do not use a programmable calculator except for checking the answer.  If you choose your initial guess correctly, the solution can be obtained in a few iterations.

From your answer, do you think that neglecting the radiation heat loss is a good assumption or not?

According to problem 1-68 (page 35), the equivalent wind chill temperature in degree C can be written as

T_equiv=33 - (33-T_ambient) [ 0.475 - 0.0126V + 0.24(V)^1/2 ], where V is the wind velocity in km/hour and T_ambient is the ambient temperature in degree C.  Using this formula to produce a wind chill temperature table if the wind speed is varied from 10 km/hr to 100 km/hr (with an increment of 10 km/hr) and the ambient temperature is 10 degree C.

Homework #2, due Friday, September 15

HW-2

1 (1990 kg/m³), 2 (235.2 kN), 3 ((a) 500 kg/m³, (b) 625 kg/m³), 4((a) 7.67 kg/s, (b) 0.976 m/s, (c) 121 sec.)

5 (3.91 m), 6 (h=1 m)

Homework #3, due Friday, September 22

HW-3(A) This is also sample test set 1-B

1. (a) T=26.3C, (b) q"=3.68 W/m²,     2. (a) W=95060 N, (b) 0.036 m,     

3. (a) P=66201 Pa, (b) dh/dt=0.0626 (m/s)

HW-3(B)    1. Q=0.0748 m³/s,     2. Power loss=10,503,150 W=14,084.9 hp

 Homework #4, due Friday, September 29

From textbook

2-28 (Tsat=104.6C), 2-29, 2-31, 2-33 (m=70.91 kg, x=0.0639), 2-39, 2-43

Homework #5, due Friday, October 6

From Textbook

2-61 (T=306.5 K), 2-64 (P=365.8 kPa), 3-39 (W=6.51 kJ), 3-52, 3-70, 3-74 (P=400 kPa)

Homework #6, due Friday, October 13

From Textbook

4-29 (1487 kW), 4-32 (965 kW), 4-45 (2.4 kg/s), 4-50 (0.431 m³/s), 4-54, 4-56

Homework #7, due Friday, October 20

Part 1

Part 2

Homework #8, due Friday, October 27

5-52, 5-74, 5-91, 5-98, 5-99, 5-102 (0.959 L/s)

Homework #9, due Friday, November 3

6-40 (T=27ºC, s_gen=0.218 kJ/K),

6-58,

6-72((a)-49.6 kW, (b)-38.3 kW, (c)-32.2 kW),

6-85,

6-87((a)T_f=57.2º C, (b) s_gen=0.034 kJ/K),

6-92

Homework #10, due Monday, Nov. 13 before 12 PM

7-86, 7-96, 7-98,

7-104 [(a) W=1366 kJ/kg, (b) h=38.9%]

7-106 [(a) P=0.677 MPa, (b) h=38.94%, (c) dm/dt=231 kg/s cooling water],

7-156 [(a) T=1092.4°C, (b) h=48.6%, (c) dm/dt=220.5 kg/s]

Homework #11, due Wednesday, Nov. 22

7-33, 7-34, 7-36, 7-60, 7-62 ((a) 43.1%, (b) 39.1%), 7-80 (F=11,000 N)

Homework#12, due Friday, Dec. 1

7-117, 7-119, 7-130

8-16 ((a) 343 kJ, (b) 286 kW, (c) 4047 W/m², (d) 40.5 W/m² C)

8-20

8-39 (k=0.112 W/m² C, cost $78.84),

Homework#13, due Friday, Dec. 8

8-59, 8-63 ((a) Q=0.0048 kWh, (b) 1959 W/m², (c) 193º C)

8-71, 8-73 (L=0.45 cm)

8-94 ((a) q=20040 W, (b) m_{ice melted}=5189 kg), 8-123