Homework Answers
b. TRUE. At the wall surface, due to no slip condition, fluid property throughout the cylinder length will be same, so value of h will also be constant.
c. TRUE. Value to h increases with turbulence, but after the entry length in a cylinder, flow becomes laminar (fully developed flow) so value of h decreases.
d. False. Due to fully developed flow and no slip condition at both the reference points, values will be same.
e. TRUE, Density difference causes natural circulation due to buoyancy
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a. (2 pts.) The film temperature, used to evaluate properties, for internal flow is the average...
Explain Convection 1. Describe the factors that affect the value of the convection coefficient 2. Explain why and how velocity and thermal boundary layers form 3. Explain how turbulence enhances c...
Explain
Convection 1. Describe the factors that affect the value of the convection coefficient 2. Explain why and how velocity and thermal boundary layers form 3. Explain how turbulence enhances convection heat transfer 4. Describe the significance of the Reynold's number, Nusselt number, and the Prandtl number 5. List common situations where external convection occurs 6. Explain the importance of the film temperature and use it to specify thermophysical properties of a fluid 7. Explain the significance of boundary layer...
3 - (50 pts.) A fluid flow in a circular pipe is heated with a constant...
3 - (50 pts.) A fluid flow in a circular pipe is heated with a constant surface temperature. The pipe diameter is set to D (in m) and the length of the pipe to L -2.5m. The inlet temperature is 300 K and the inlet velocity is uniform. Use the following air properties: p=1 kg/m', u=2x10* Pa-s, k=0.03 W/m-K. The Reynolds number to Rep - 200 and the Prandt number to Pr=1.75. A section of the pipe is heated with...
2- (50 pts.) A fluid flow in a circular pipe is heated with a constant heat...
2- (50 pts.) A fluid flow in a circular pipe is heated with a constant heat flux. The pipe diameter is set to D=0.2 m and the length of the pipe to L = 1.0 m. The inlet temperature is 300 K and the inlet velocity is uniform. Use the following air properties: p= 1 kg/m?, u=4x10-5 Pa-s, k=0.03 W/m-K. The Reynolds number is Rep and the Prandtl number to Pr=1. A section of the pipe is heated with a...
Mechanical Engineering Heat Transfer chapter &(Internal Convection) will give a like. ONLY SO...
Mechanical Engineering Heat Transfer chapter &(Internal
Convection) will give a like.
ONLY SOLVE PART C and D
Problem 1 (Short Answer) Answer the following questions in 2-4 sentences a. Describe the features of the entrance region and the fully developed region of internal flow. b. Explain why the mean temperature changes along the axial direction in internal flow, while the free-stream temperature does not change in external flow. of constant heat flux and constant wall temperature. expect the velocity boundary...
Which of the following statements are true (could be multiple) for internal flow through a pipe?...
Which of the following statements are true (could be multiple) for internal flow through a pipe? In laminar flow, the Nusselt is higher for constant wall temperature compared to that for constant heat flux. In turbulent flow, the Nusselt number is higher at the pipe exit than at the pipe entrance In laminar flow, the Nusselt number is lower at the pipe exit than at the pipe entrance In laminar fully developed flow, the Nusselt number is independent of Reynolds...
State whether each statement below is True (T) or False (El. Use your best engineering judgment"....
State whether each statement below is True (T) or False (El. Use your best engineering judgment". 1. Phenomenological laws classify and describe phenomena based on observation of macroscopic behavior without explanation of microscopic behavior. 2. Fourier's Law of Heat Conduction states that the heat flux is directly proportional to the temperature gradient. 3. A "gray surface" absorbs the same magnitude of radiation as a “black surface". 4. A "black surface" surfaces emit less radiation than does a "gray surface". 5....
(2 pts) Heat is transferred from a hot fluid (temperature T1 and heat transfer coefficient h2)...
(2 pts) Heat is transferred from a hot fluid (temperature T1 and heat transfer coefficient h2) through a plane wall of thickness 8, surface area A and the thermal conductivity k. The thermal resistance for the set up is + (a) AC ) (b) A (i + + ) (c) 2 (na + + n2) (d) A (na + b +h2) (2 pts) An increase in convective heat transfer coefficient over a fin will (a) increase effectiveness (b) decrease effectiveness...
use table A-15 kinematic viscosity 6. Consider a 2-m long smooth cylindrical pipe of 5 cm...
use table A-15 kinematic viscosity
6. Consider a 2-m long smooth cylindrical pipe of 5 cm internal diameter, that is maintained at a constant surface temperature. Air flows through the tube at 0.5 m/s. Air enters the pipe at 20°C and leaves it at 60°C. Determine: (a) Is the flow laminar or turbulent? (b) Is the flow fully developed? (c) What Nu number correlation will you use to find h? Find Nu. (d) Find the convection heat transfer coefficient (h)...
EMERGENCY. please reply fast 7- A pipe of 120 mm internal diameter 2.2 m long carries thermally an hydrodynamical fully developed flow at 1 is maintained at a temperature of go c temperature of th...
EMERGENCY. please reply fast
7- A pipe of 120 mm internal diameter 2.2 m long carries thermally an hydrodynamical fully developed flow at 1 is maintained at a temperature of go c temperature of the fluid reaches 50'C. Case b) Find roughness is o.26 mm and your findings. 21.5 kg/s. The pipe is smooth and Case a) Find h where the bulk the fluid temperature reaches 5o'С. Discuss nended in quiescent air Aihat
7- A pipe of 120 mm internal...
2) (35 pt) Atmospheric air at 25 Centers a duct having a cross section of an...
2) (35 pt) Atmospheric air at 25 Centers a duct having a cross section of an equilateral triangle 2 cm on a side with a velocity of 1.5 m/s. The length of the duct is 10 m. A constant heat flux is imposed on the duct wall. The mean temperature of the air at the duct exit is 75 °C. a. Is the flow at the duct exit hydrodynamically and thermally fully developed? Show. T-75 °C b. Calculate the convection...
Explain
Convection 1. Describe the factors that affect the value of the convection coefficient 2. Explain why and how velocity and thermal boundary layers form 3. Explain how turbulence enhances convection heat transfer 4. Describe the significance of the Reynold's number, Nusselt number, and the Prandtl number 5. List common situations where external convection occurs 6. Explain the importance of the film temperature and use it to specify thermophysical properties of a fluid 7. Explain the significance of boundary layer...
3 - (50 pts.) A fluid flow in a circular pipe is heated with a constant surface temperature. The pipe diameter is set to D (in m) and the length of the pipe to L -2.5m. The inlet temperature is 300 K and the inlet velocity is uniform. Use the following air properties: p=1 kg/m', u=2x10* Pa-s, k=0.03 W/m-K. The Reynolds number to Rep - 200 and the Prandt number to Pr=1.75. A section of the pipe is heated with...
2- (50 pts.) A fluid flow in a circular pipe is heated with a constant heat flux. The pipe diameter is set to D=0.2 m and the length of the pipe to L = 1.0 m. The inlet temperature is 300 K and the inlet velocity is uniform. Use the following air properties: p= 1 kg/m?, u=4x10-5 Pa-s, k=0.03 W/m-K. The Reynolds number is Rep and the Prandtl number to Pr=1. A section of the pipe is heated with a...
Mechanical Engineering Heat Transfer chapter &(Internal
Convection) will give a like.
ONLY SOLVE PART C and D
Problem 1 (Short Answer) Answer the following questions in 2-4 sentences a. Describe the features of the entrance region and the fully developed region of internal flow. b. Explain why the mean temperature changes along the axial direction in internal flow, while the free-stream temperature does not change in external flow. of constant heat flux and constant wall temperature. expect the velocity boundary...
Which of the following statements are true (could be multiple) for internal flow through a pipe? In laminar flow, the Nusselt is higher for constant wall temperature compared to that for constant heat flux. In turbulent flow, the Nusselt number is higher at the pipe exit than at the pipe entrance In laminar flow, the Nusselt number is lower at the pipe exit than at the pipe entrance In laminar fully developed flow, the Nusselt number is independent of Reynolds...
State whether each statement below is True (T) or False (El. Use your best engineering judgment". 1. Phenomenological laws classify and describe phenomena based on observation of macroscopic behavior without explanation of microscopic behavior. 2. Fourier's Law of Heat Conduction states that the heat flux is directly proportional to the temperature gradient. 3. A "gray surface" absorbs the same magnitude of radiation as a “black surface". 4. A "black surface" surfaces emit less radiation than does a "gray surface". 5....
(2 pts) Heat is transferred from a hot fluid (temperature T1 and heat transfer coefficient h2) through a plane wall of thickness 8, surface area A and the thermal conductivity k. The thermal resistance for the set up is + (a) AC ) (b) A (i + + ) (c) 2 (na + + n2) (d) A (na + b +h2) (2 pts) An increase in convective heat transfer coefficient over a fin will (a) increase effectiveness (b) decrease effectiveness...
use table A-15 kinematic viscosity
6. Consider a 2-m long smooth cylindrical pipe of 5 cm internal diameter, that is maintained at a constant surface temperature. Air flows through the tube at 0.5 m/s. Air enters the pipe at 20°C and leaves it at 60°C. Determine: (a) Is the flow laminar or turbulent? (b) Is the flow fully developed? (c) What Nu number correlation will you use to find h? Find Nu. (d) Find the convection heat transfer coefficient (h)...
EMERGENCY. please reply fast
7- A pipe of 120 mm internal diameter 2.2 m long carries thermally an hydrodynamical fully developed flow at 1 is maintained at a temperature of go c temperature of the fluid reaches 50'C. Case b) Find roughness is o.26 mm and your findings. 21.5 kg/s. The pipe is smooth and Case a) Find h where the bulk the fluid temperature reaches 5o'С. Discuss nended in quiescent air Aihat
7- A pipe of 120 mm internal...
2) (35 pt) Atmospheric air at 25 Centers a duct having a cross section of an equilateral triangle 2 cm on a side with a velocity of 1.5 m/s. The length of the duct is 10 m. A constant heat flux is imposed on the duct wall. The mean temperature of the air at the duct exit is 75 °C. a. Is the flow at the duct exit hydrodynamically and thermally fully developed? Show. T-75 °C b. Calculate the convection...
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