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evablogger [386]
3 years ago
12

Flue gases from an incinerator are released to atmosphere using a stack that is 0.6 m in diameter and 10.0 m high. The outer sur

face of the stack is at 40°C and the surrounding air is at 10°C. Determine the rate of heat transfer from the stack, assuming
(a) there is no wind and
(b) the stack is exposed to 20 km/h winds.
Engineering
1 answer:
Goshia [24]3 years ago
7 0

Answer:

(a) Rate of heat transfer assuming there is no wind is 152.70J/s

(b) Rate of heat transfer assuming the stack is exposed to 20km/h winds is 151.49J/s

Explanation:

Q/t = KA(T2 - T1)/d

Range of heat transfer coefficient (K) for flue gases is 60-180W/mk

Assuming K=180W/mk, diameter (d) =0.6m, A=3.142×0.6^2/4 = 028278m^2, distance (d) = 10m, T2=40°C, T1=10°C

(a) Q/t = 180×0.28278×(40-10)/10 = 180×0.28278×30/10 = 152.70J/s

(b) V= 20km/h=20×1000/3600m/s= 5.6m/s, t=d/v=10/5.6=1.8s

Q = KA(T2 - T1)/V = 180×0.28278×(40 - 10)/5.6 = 180×0.28278×30/5.6 = 272.68J

Q/t = 272.68J/1.8s = 151.48J/s

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lapo4ka [179]
Aluminum
Aluminum siding is out of date and really has no advantages in today’s market. It dents, it’s difficult to keep clean, and it’s hard to update it once it’s installed. Aluminum siding is not recommended, and most professional contractors won’t even install it.

Vinyl
Today’s mainstream siding material is vinyl. It is the most economical type of siding, coming in at $4 to $5 per square foot.

Available in a wide variety of colors, vinyl siding not only protects your home, it can make a statement. You can choose from whites, ivories, grays, browns, reds, greens and even blues — there’s a color for everyone.

In addition, vinyl is a complete self-flushing water-exclusion system. It is made to be water repellent and durable in any kind of weather. Its lightweight footprint makes it easy to install, which minimizes expenses.

Vinyl is low-maintenance and requires only periodic cleaning with a power washer every few years – more if you want it to really shine.

Premium vinyl
A step up from regular vinyl, premium vinyl gives you a more wood-like appearance. It’s usually a thicker vinyl that looks more rigid because it has no oil canning, as lighter vinyl does.

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Natural wood
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Fiber cement siding
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5 0
3 years ago
Create a program named IntegerFacts whose Main() method declares an array of 10 integers.Call a method named FillArray to intera
musickatia [10]

Answer:

C# codee

using System;

class IntegerFacts

{

static void Main()

{

int[] x = new int[10];

int sum = 0;

int siz = 0, high = 0, low = 0, avg = 0;

siz = FillArray(x);

Statistics(x, ref high, ref low, ref sum, ref avg, siz);

Console.Write("The highest value is " + high);

Console.Write("\nThe lowest value is " + low);

Console.Write("\nThe sum of the values is " + sum);

Console.Write("\nThe average is " + avg);

}

static void Statistics (int [] b, ref int h, ref int l, ref int s, ref int a, int size)

{

if (size == 0)

h = l = s = a = 0;

else

{

int i =0;

l = 999;

h = 0;

s = 0;

for (; i < size;++i)

{

if(b[i] > h)

h = b[i];

if(b[i] < l)

l = b[i];

s += b[i];

}

a = s / size;

}

}

static int FillArray (int[] a)

{

int i = 0, count = 0;

int intTemp =0 ;

string temp;

for(i = 0 ; i < 10 ; i++)

{

Console.Write("Enter element number"+(i+1) +" : ");

temp = Console.ReadLine();

if (int.TryParse(temp, out intTemp)) {

if (intTemp != 999)

{

a[i] = intTemp;

count++;

}

else

break;

}

else

{

Console.Write("\n\nOops.. You entered a wrong number. Try again \n\n");

i--;

}

}

return count;

}

}

Explanation:

The output of the above program is given in the attached file.

8 0
4 years ago
A 0.2‐kg particle P is constrained to move along the vertical‐plane circular slot of radius r = 0.5 m and is confined to the slo
Pavel [41]

Answer:

● The force N exerted on the particle by the circular constraint= -2.885 N

● The force R exerted on it by the slotted arm= 1.599 N

Explanation:

The solution and complete explanation for the above question and mentioned conditions is given below in the attached document.i hope my explanation will help you in understanding this particular question.

8 0
3 years ago
Ethylene (C2H4) gas enters a well-insulated reactor and reacts completely with 400% of theoretical air, each at 25°C, 2 atm. The
GuDViN [60]

Answer:see explanation.

Explanation:

(a).The equation of reaction is;

C2H4 + 3(O2 + 3.76N2) -----> 2CO2 + 2H2O + 11.28 N2.

Theoretical air is the amount of air that will allow the complete combustion of the fuel. Air contains 21% of oxygen,79% of Nitrogen. Thus, the molecular mass of air = 29 [Kg/Kmol] . The number of oxygen needed to oxidize the hydrocarbon(C2H4) is 79/21= 3.76 moles of Nitrogen.

(b). N(total) =2+2+11.28 =15.28 kmoles of product

15.28[h(T) - h°] of air

= 15.28(Mass of air) (Cp,1000k)

T(adiabatic) = 802,310 kJ/k. Mole.

When mass of air= 29 Kg/ k.mol

Cp,1000k = 1.142 kJ.k which is the specific heat capacity of air.

T(adiabatic) = 1275k -----> assuming all the products are air.

(C). 2{∆h} co2 + 2{∆h} H20 +11.28 {∆h} N2

After series of calculations and checking of tables:

S(o2) = 320.173 - 8.314 ln 0.12= 337.46 kJ/ K.mol.k

S(H2O)= 273.986- 8.314 ln 0.1406 = 290.30 KJ/ kmol. K

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= 2(337.46) + 2(290.30)+11.28(261.07)-360.79-3(218.01)-11.28(193.46)

=1003.3378 kJ/kmol. K

5 0
3 years ago
Which construction material can workers erect at the fastest rate?
mina [271]

Answer:

Fabrication benefits

Explanation:

Onsite construction can certainly begin more quickly when you are using concrete, stone, or brick. However, total construction time will lag behind that of building with steel. These materials require time to prepare and cure; and they result in more waste to move off site and dispose of.

7 0
3 years ago
Read 2 more answers
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