Answer:
t=5.5 mm
Heat dissipation per unit length = 90.477 W/m
Explanation:
Given that
Diameter d = 5 mm ⇒r = 2.5 mm
Conductivity of insulated material K = 0.16 W/mK
Heat transfer coefficient = 20
When thickness reaches up to critical radius of insulation then heat dissipation will be maximum
We know that critical radius of insulation of wire is given as follow
Now by putting the values
So the thickness of insulation
t=8-2.5 mm
t=5.5 mm
As we know that heat transfer due to convection given as follows
Q = hAΔ T
Q=20 x 2 x π x 0.008 x (120-30)
Q = 90.477 W/m
So heat dissipation per unit length = 90.477 W/m
Answer:
0.4167 ft/s
Explanation:
The law of conservation is applied to point A and B.
This gives:
Hence, is the kinetic energy at the position A
is the velocity at point A
Considering point A, the kinetic energy at the point will be:
The potential energy will be:
Hence, is the potential energy and is the kinetic energy
The potential energy is given by the following:
substituting 1 lb for mg gives 0.4167 ft for r
Then the velocity,
Answer:
- |z*| = r , ∠(z*) = -∅
- |z²| = r² , ∠(z²) = 2∅
- |jz| = r , ∠(jz) = ∅
- |zz*| = r² , ∠(zz*) = 0
- |z/z*| = 1 , ∠(z/z*) = 2∅
- |1/z| = r ⁻¹ , ∠(1/z) = -∅
Explanation:
view image
1.) The * mean you take the conjugate of the value. This means you change the sign of the imaginary part, so if it's positive, turn it negative and vice versa.
2.) The magnitude with an exponent can have the exponent moved outside the magnitude. |zⁿ| = |z|ⁿ
The angle multiplies with its exponent instead. ∠zⁿ = n∠z
3.) This part is just testing if you can convert the number using the eulers formula and convert back.
The magnitude could be found using the distance formula. √(R² + I²)
The angle could be found using tan⁻¹(Imaginary/Real).
4.) Magnitude of a product could be split up. |zv| = |z|·|v|
Angle of a product could be splitted up and added. ∠(zv) = ∠z + ∠v
5.) Simplify it first using some algebra and use the euler's identity to identify the magnitude and angle. It takes in a form like this:
A is your magnitude, ∅ is your angle.
6.) Same rule as part 2
Answer:
work=281.4KJ/kg
Power=4Kw
Explanation:
Hi!
To solve follow the steps below!
1. Find the density of the air at the entrance using the equation for ideal gases
where
P=pressure=120kPa
T=20C=293k
R= 0.287 kJ/(kg*K)=
gas constant ideal for air
2.find the mass flow by finding the product between the flow rate and the density
m=(density)(flow rate)
flow rate=10L/s=0.01m^3/s
m=(1.43kg/m^3)(0.01m^3/s)=0.0143kg/s
3. Please use the equation the first law of thermodynamics that states that the energy that enters is the same as the one that must come out, we infer the following equation, note = remember that power is the product of work and mass flow
Work
w=Cp(T1-T2)
Where
Cp= specific heat for air=1.005KJ/kgK
w=work
T1=inlet temperature=20C
T2=outlet temperature=300C
w=1.005(300-20)=281.4KJ/kg
Power
W=mw
W=(0.0143)(281.4KJ/kg)=4Kw
Answer and Explanation:
The parameter which affect the heat transfer coefficient in a heat exchanger are
- Viscosity of the liquid, thermal conductivity,density , specific heat
- Geometry of heat exchanger that length width and height of heat exchanger
- Velocity of fluids
- It also depends on the type of flow of liquid that laminar flow ,turbulent flow