1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
andrey2020 [161]
3 years ago
7

In a manufacturing facility, 2-in-diameter brass balls (k = 64.1 Btu/h·ft·°F, rho = 532 lbm/ft^3, and cp = 0.092 Btu/lbm·°F) ini

tially at 360°F are quenched in a water bath at 120°F for a period of 2 min at a rate of 120 balls per minute. The convection heat transfer coefficient is 42 Btu/h·ft^2·°F. Take I to be the initial temperature. Determine:
a. The temperature of the balls after quenching.
b. The rate at which heat needs to be removed from the water in order to keep its temperature constant at 1200F.
Engineering
2 answers:
noname [10]3 years ago
5 0

Answer:

A) 205.872°F

B) 2172 Btu/min

Explanation:

A) First of all, we will compute the characteristic length and the Biot number to see if the lumped parameter analysis is applicable.

Thus;

Lc = V/A = (πD³/6)/(πD²)

Simplifying; L = D/6

Since D = 2 inches or in ft as D= 0.1667

Lc = 2/6 = 1/3 inches

Now we have to convert to feet because K is in ft.

Thus Lc = 1/3 x 0.0833 = 0.0278 ft

Formula for Biot number is;

Bi = hLc/k

Thus, Bi = (42 x 0.0278)/641 = 0.018

Since the biot number is less than 0.1,we will make use of the lumped parameter analysis which is given by;

T = T∞ + (Ti - T∞)e^(-bt) and

b = h/(ρ(Cp)(Lc))

Let's find b first before the temperature T.

Thus; b = 42/(532 x 0.092 x 0.0278) = 30.9 per hr

Now lets find the temperature after 2 minutes. For sake of ease of calculation, let's convert 2 minutes to hours to give; 2/60 = 0.033 hr

From the question, T∞ = 120°F and Ti = 360°F

So, T = 120 + (360 - 120)e^(-30.9 x 0.033)

T = 120 + 240e^(-1.02897)

T = 120 + (240 x 0.3578) = 205.872°F

B) The heat transfer to each ball is the product of mass, heat capacity and difference between

the initial and final temperature.

Thus;

Q = M(Cp)(Ti - T∞)

We know that Density = Mass/Volume and thus mass(M) =

Density x Volume = ρV

So;

Q = ρV(Cp)(Ti - T∞)

= 532 x ((π x 0.1667³)/6) x (0.092) (360 - 205.872)

= 532 x 0.0024 x 0.092 x 154.128 = 18.1 Btu

So for 120 balls per minute the total heat removal ;

18.1 Btu x (120 per minutes) = 2172 Btu per minutes

bekas [8.4K]3 years ago
4 0

Answer:

Explanation:

First we compute the characteristic length and the Biot number to see if the lumped parameter

analysis is applicable.

Since the Biot number is less than 0.1, we can use the lumped parameter analysis. In such an

analysis, the time to reach a certain temperature is given by the following

From the data in the problem we can compute the parameter, b, and then compute the time for

the ratio (T – T)/(Ti

– T)

You might be interested in
Energy transfer in mechanical systems: During steady-state operation, a mechanical gearbox receives 70 KW of input power through
Degger [83]

Answer:

Heat transfer rate(Q)= 1.197kW

Power output(W)=68.803kW

3 0
3 years ago
Rough Riders Inc. manufactures jeans in the cutting and sewing process. Jeans are manufactured in 50-jean batch sizes. The cutti
miskamm [114]

Answer: me and ten points now

Explanation:

3 0
3 years ago
Q7. A cylindrical rod of 1040 steel originally 15.2 mm (0.60 in.) in diameter is to be cold worked by drawing; the circular cros
umka2103 [35]

Answer:

11.2mm or 0.45in

Explanation:

The percent cold work, attendant tensile strength and ductility if drawing is carried out without interruption is given by the equation you will find in the attached file.

Please go through the attached file for a step by step solution to this question.

5 0
3 years ago
How high a building could fire hoses effectively spray from the ground? Fire hose pressures are around 1 MPa. (It is also said t
Mrac [35]

Answer:

z_{2} = 91.640\,m

Explanation:

The phenomenon can be modelled after the Bernoulli's Principle, in which the sum of heads related to pressure and kinetic energy on ground level is equal to the head related to gravity.

\frac{P_{1}}{\rho\cdot g} + \frac{v_{1}^{2}}{2\cdot g}= z_{2}+\frac{P_{2}}{\rho\cdot g}

The velocity of water delivered by the fire hose is:

v_{1} = \frac{(300\,\frac{gal}{min} )\cdot(\frac{3.785\times 10^{-3}\,m^{3}}{1\,gal} )\cdot(\frac{1\,min}{60\,s} )}{\frac{\pi}{4}\cdot (0.3\,m)^{2}}

v_{1} = 0.267\,\frac{m}{s}

The maximum height is cleared in the Bernoulli's equation:

z_{2}= \frac{P_{1}-P_{2}}{\rho\cdot g} + \frac{v_{1}^{2}}{2\cdot g}

z_{2}= \frac{1\times 10^{6}\,Pa-101.325\times 10^{3}\,Pa}{(1000\,\frac{kg}{m^{3}} )\cdot(9.807\,\frac{m}{s^{2}} )} + \frac{(0.267\,\frac{m}{s} )^{2}}{2\cdot (9.807\,\frac{m}{s^{2}} )}

z_{2} = 91.640\,m

7 0
3 years ago
Explain the term electric current as used in engineering principles​
vodomira [7]

Answer:

<em>Electric current is the movement of electrons through a wire. Electric current is measured in amperes (amps) and refers to the number of charges that move through the wire per second. If we want current to flow directly from one point to another, we should use a wire that has as little resistance as possible.</em><em>Current is directly proportional to voltage, inversely proportional to resistance. One of the most common electrical measurements you'll use is the watt, a unit of electrical power: W (Watts) = E (Volts) x I (Amperes). The quantity of electric charge is measured in coulombs.</em><em>They can even pass through bones and teeth. This makes gamma rays very dangerous. They can destroy living cells, produce gene mutations, and cause cancer.</em>

Explanation:

hey mate this is the best answer if you're studying engineering!

8 0
3 years ago
Read 2 more answers
Other questions:
  • Match each titration term with its definition.
    15·1 answer
  • What are the factors of production in business? Land, labor, and capital land, capital, and interest land, labor, and customer b
    10·2 answers
  • A simply supported wood roof beam is loaded with single point dead and roof live loads applied at midspan (PD = 400 lb, PLr = 16
    9·1 answer
  • 0 - 1"<br> -20<br> -15<br> -10<br> 5<br> 0 1 2 3<br> 0
    14·1 answer
  • You apply a force of 19 lbs on to the end of a lever to lift a crate. The resistance of the load is 106 lbs. Calculate the
    13·1 answer
  • Difference between theory and practice?​
    10·1 answer
  • A 2-bit positive-edge triggered register has data inputs d1, d0, clock input clk, and outputs q1, q0. Data inputs d1d0 are 01 an
    15·1 answer
  • Whats the purpose of the keyway
    13·1 answer
  • Technician A says that synthetic blend oil has the same service life as that of full synthetic oils. Technician B says that conv
    6·1 answer
  • As the driver of the red SUV, what are your options for navigating this roundabout?
    6·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!