Answer:
Explanation:
Mean temperature is given by
![T_mean = \frac{T_i + T_ \infinity}{2}\\\\T_mean = \frac{200 + 15}{2}](https://tex.z-dn.net/?f=T_mean%20%3D%20%5Cfrac%7BT_i%20%2B%20T_%20%5Cinfinity%7D%7B2%7D%5C%5C%5C%5CT_mean%20%3D%20%5Cfrac%7B200%20%2B%2015%7D%7B2%7D)
Tmean = (Ti + T∞)/2
![T_mean = 107.5^{0}](https://tex.z-dn.net/?f=T_mean%20%3D%20107.5%5E%7B0%7D)
Tmean = 107.5⁰C
Tmean = 107.5 + 273 = 380.5K
Properties of air at mean temperature
v = 24.2689 × 10⁻⁶m²/s
α = 35.024 × 10⁻⁶m²/s
= 221.6 × 10⁻⁷N.s/m²
= 0.0323 W/m.K
Cp = 1012 J/kg.K
Pr = v/α = 24.2689 × 10⁻⁶/35.024 × 10⁻⁶
= 0.693
Reynold's number, Re
Pv = 4m/πD²
where Re = (Pv * D)/![\mu](https://tex.z-dn.net/?f=%5Cmu)
Substituting for Pv
Re = 4m/(πD
)
= (4 x 0.003)/( π × 6 ×10⁻³ × 221.6 × 10⁻⁷)
= 28728.3
Since Re > 2000, the flow is turbulent
For turbulent flows, Use
Dittus - Doeltr correlation with n = 0.03
Nu = 0.023Re⁰⁸Pr⁰³ = (h₁D)/k
(h₁ × 0.006)/0.0323 = 0.023(28728.3)⁰⁸(0.693)⁰³
(h₁ × 0.006)/0.0323 = 75.962
h₁ = (75.962 × 0.0323)/0.006
h₁ = 408.93 W/m².K
Answer:
The correct answer is: the following factors are needed to properly consider while selecting a brake or clutch:
-Engagement
-Friction
-Electromagnetic
-Mechanical
-Actuation
-Electric
-Fluid power
-Self-actuation
-Key concepts
-Application notes
-Selection criteria
Explanation:
Clutches and brakes are important devices in many rotating drive systems, it is very important to guarantee the security and the proper function of them accomplishing a high quality parameters in those factors.
Answer: 150m
Explanation:
The following can be depicted from the question:
Dimensions of outer walls = 9.7m × 14.7m.
Thickness of the wall = 0.30 m
Therefore, the plinth area of the building will be:
= (9.7 + 0.30/2 + 0.30/2) × (14.7 × 0.30/2 + 0.30/2)
= 10 × 15
= 150m