Presents the relevant parameters to be kept in mind when using the following types of motors: 1. AC induction motor 2. BLDC moto
2 answers:
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Answer:
127.42m
Explanation:
The air pressure can be understood as the weight exerted by the air column on a body, for this case we must remember that the pressure is calculated by the formula P=αgh, Where P=pressure, h=gravity, h= height,α=density
So what we must do to solve this problem is to find the length of the air column above and below the building and then subtract them to find the height of the building, taking into account the above the following equation is inferred
h2-h1= building height=H
P1=100kPa=100.000Pa
P2=98.5kPa=98.500Pa
α=1.2 kg/m^3
g=9.81m/s^2
Answer:
Re=100,000⇒Q=275.25
Re=500,000⇒Q=1,757.77
Re=1,000,000⇒Q=3060.36
Explanation:
Given:
For air =25°C ,V=8 m/s
For surface =179°C
L=2.75 m ,b=3 m
We know that for flat plate
⇒Laminar flow
⇒Turbulent flow
<u> Take Re=100,000:</u>
So this is case of laminar flow
From standard air property table at 25°C
Pr= is 0.71 ,K=26.24
So
Nu=187.32 ()
187.32=
⇒h=1.78
heat transfer rate =h
=275.25
<u> Take Re=500,000:</u>
So this is case of turbulent flow
Nu=1196.18 ⇒h=11.14
heat transfer rate =h
=11.14(179-25)
= 1,757.77
<u> Take Re=1,000,000:</u>
So this is case of turbulent flow
Nu=2082.6 ⇒h=19.87
heat transfer rate =h
=19.87(179-25)
= 3060.36