The purpose of adjusting your mirrors is to ________

Convection ovens operate on the principle of inducing forced convection inside the oven chamber with a fan. A small cake is to b

coldgirl [10]

Answer:

A) q'_free = 3146.41 W/m²

B) q'_forced = 7521.41 W/m²

Explanation:

We are given;

Free convection coefficient; h_fr = 5 W/m²K

Force convection coefficient; h_forced = 30 W/m²K

Emissivity; ε = 0.95

Temperature of surrounding which is equal to temperature of air; T_s = T_air = 200°C = 473K

Initial temperature; T_i = 25°C = 298K

A) Now, since the convection feature is disabled, the mode of heat transfer associated with this condition is through free convection and radiation.

Thus, the formula for the heat flux under this condition is given as;

q'_free = q'_free convection + q'_radiation

q'_free convection = h_free(T_∞ - T_i) where T_∞ is equivalent to the value of T_air

Also, q'_radiation = ε•σ((T_air)⁴ - (T_i)⁴)

Where, σ is stephan boltzmann constant and has a constant value of 5.67 × 10^(−8) W/m²K⁴

Thus, rewriting;

q'_free = q'_free convection + q'_radiation

We have;

q'_free = [h_free(T_∞ - T_i)] + [ε•σ((T_air)⁴ - (T_i)⁴)]

Plugging in the relevant values to obtain;

q'_free = [5(473 - 298)] + [0.95•5.67 × 10^(−8)((473)⁴ - (298)⁴)]

q'_free = 875 + 2271.41

q'_free = 3146.41 W/m²

B) Now, in this case, since the convection feature is disabled, the mode of heat transfer associated with this condition is through forced convection and radiation.

Thus, the formula for the heat flux under this condition is given as;

q'_forced = q'_forced convection + q'_radiation

Where;

q'_forced convection = h_forced(T_∞ - T_i) where T_∞ is equivalent to the value of T_air

Also, q'_radiation = ε•σ((T_air)⁴ - (T_i)⁴)

Thus, rewriting;

q'_forced = q'_free convection + q'_radiation

We have;

q'_forced = [h_forced(T_∞ - T_i)] + [ε•σ((T_air)⁴ - (T_i)⁴)]

Plugging in the relevant values to obtain;

q'_forced = [30(473 - 298)] + [0.95•5.67 × 10^(−8)((473)⁴ - (298)⁴)]

q'_forced = 5250 + 2271.41

q'_forced = 7521.41 W/m²

7 0

4 years ago

Select the correct answer.

Rina8888 [55]

A: Inexhaustible resources are limited

is true

6 0

3 years ago

What is the stress concentration factor of a shaft in torsion, where D=1.25 in. and d=1 in. and the fillet radius is, r=0.2 in.a

klio [65]

Answer:

Concentration factor will be 1.2

So option (C) will be correct answer

Explanation:

We have given outer diameter D = 1.25 in

And inner diameter d = 1 in and fillet ratio r = 0.2 in

So $\frac{r}{d}$ ratio will be $=\frac{0.2}{1}=0.2$

And $\frac{D}{d}$ ratio will be $=\frac{1.25}{1}=1.25$

Now from the graph in shaft vs torsion the value of concentration factor will be 1.2

So concentration factor will be 1.2

So option (C) will be correct answer.

6 0

3 years ago

How do you make a robotic dog

fredd [130]

In order to create a robotic dog, you are needing the necessary parts to create Goddard from Jimmy nutreon boy genius

7 0

3 years ago

Read 2 more answers

The Double.parseDouble() method requires a String argument, but it fails if the String cannot be converted to a floating-point n

LuckyWell [14K]

Answer:

import java.util.Scanner;
public class TryToParseDouble {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
double num;
try{
System.out.print("Input a number: ");
num = Double.parseDouble(input.nextLine());
}catch(NumberFormatException e){
num = 0;
System.out.println("Invalid input! It should be a number in double type");
}
System.out.println(num);
}
}

Explanation:

Firstly, create a Scanner object to get user input (Line 5).

Next, create a try block and prompt user to input a number and use Double.parseDouble() method to convert the input to double type in the block (Line 8-10).

Next, create a catch block to catch a NumberFormatException. In the Catch block, set the num to zero and then print out a message to inform user about the invalid input (Line 12-14).

Lastly, display the number (Line 16).

5 0

3 years ago

The purpose of adjusting your mirrors is to _________.