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Mechanical Engineering Heat Transfer chapter &(Internal Convection) will give a like. ONLY SO...
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...
Use the integral method for boundary layer flow and convective heat transfer over a flat plate he...
Use the integral method for boundary layer flow and convective heat transfer over a flat plate heated by maintaining a constant heat flux q"w, for the case of very low Prandtl number, Pr0. Assume that the free stream velocity of the fluid, U, and free stream temperature, T-do not vary with x. Using the integral form of energy equation, show that under these conditions: (a) the temperature profile, (T- T) is given by, 41 2 CT-T oa (b) the wall...
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...
(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...
a. (2 pts.) The film temperature, used to evaluate properties, for internal flow is the average...
a. (2 pts.) The film temperature, used to evaluate properties, for internal flow is the average of the surface temperature and the external free stream fluid temperature. True or False. 1. b. (2 pts.) The local convection coefficient, h, around the circumference of a cylinder in cross flow is constant (it does not vary with position as you travel around the cylinder.) True or False c. (2 pts.) For internal fully developed flow the convection coefficient, h, decreases as the...
Superimposed free convection over forced convection will yield higher heat trans- fer coefficients for: (a) gas...
Superimposed free convection over forced convection will yield higher heat trans- fer coefficients for: (a) gas heating in a horizontal tube (b)iquid cooling in a horizontal tube (c) liquid heating in a vertical tube with upflow (d) gas cooling in a vertical tube with downflow 7.38 7.39 The free convection effect in a forced flow may be significant for (a) small (T T (c) shell-and-tube exchanger (b) highly compact exchanger (d) high Reynolds number 7.35 Compared to the constant-viscosity case,...
1. (25 pts) Answer the following conceptual questions. Write down full explanations and derivations on a...
1. (25 pts) Answer the following conceptual questions. Write down full explanations and derivations on a clean piece of paper. h, 8 h(x) 80) 1 a. The effect of transition from laminar to turbulent flow on local velocity boundary layer thickness, 8(x) and local convection coefficient, h(x) for steady flow over an isothermal plate is illustrated in the following figure. Why does the convection coefficient decrease with x in the laminar region? How would the local heat flux change 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...
Clear solutions please fully worked out for a thumbs up, thanks! . Compare the external flows...
Clear solutions please fully worked out for a thumbs up,
thanks!
. Compare the external flows of two different fluids over a flat plate held at a constant T,; air at a free-stream speed Ux-3 m and temperature Too-250 K to that of engine oil at a free-stream speed Un-3 ! ! and temperature T 400 K. For laminar flow over a flat plate, the velocity boundary layer thickness is given by δ- (In the absence of a known surface...
PROBLEM 3 (45 points) The condenser of a large steam power plant is a heat exchanger...
PROBLEM 3 (45 points) The condenser of a large steam power plant is a heat exchanger in which steam is condensed to liquid water. Assume the condenser to be a parallel flow shell-and-tube heat exchanger consisting of a single shell and 1x10 tubes, each executing two passes. The inner diameter of tubes is D = 50 mm and its thickness is 5 mm (Do not ignore the thickness). The steam condenses on their outer surface. Thermal conductivity of the tube...
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...
Use the integral method for boundary layer flow and convective heat transfer over a flat plate heated by maintaining a constant heat flux q"w, for the case of very low Prandtl number, Pr0. Assume that the free stream velocity of the fluid, U, and free stream temperature, T-do not vary with x. Using the integral form of energy equation, show that under these conditions: (a) the temperature profile, (T- T) is given by, 41 2 CT-T oa (b) the wall...
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...
(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...
a. (2 pts.) The film temperature, used to evaluate properties, for internal flow is the average of the surface temperature and the external free stream fluid temperature. True or False. 1. b. (2 pts.) The local convection coefficient, h, around the circumference of a cylinder in cross flow is constant (it does not vary with position as you travel around the cylinder.) True or False c. (2 pts.) For internal fully developed flow the convection coefficient, h, decreases as the...
Superimposed free convection over forced convection will yield higher heat trans- fer coefficients for: (a) gas heating in a horizontal tube (b)iquid cooling in a horizontal tube (c) liquid heating in a vertical tube with upflow (d) gas cooling in a vertical tube with downflow 7.38 7.39 The free convection effect in a forced flow may be significant for (a) small (T T (c) shell-and-tube exchanger (b) highly compact exchanger (d) high Reynolds number 7.35 Compared to the constant-viscosity case,...
1. (25 pts) Answer the following conceptual questions. Write down full explanations and derivations on a clean piece of paper. h, 8 h(x) 80) 1 a. The effect of transition from laminar to turbulent flow on local velocity boundary layer thickness, 8(x) and local convection coefficient, h(x) for steady flow over an isothermal plate is illustrated in the following figure. Why does the convection coefficient decrease with x in the laminar region? How would the local heat flux change 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...
Clear solutions please fully worked out for a thumbs up,
thanks!
. Compare the external flows of two different fluids over a flat plate held at a constant T,; air at a free-stream speed Ux-3 m and temperature Too-250 K to that of engine oil at a free-stream speed Un-3 ! ! and temperature T 400 K. For laminar flow over a flat plate, the velocity boundary layer thickness is given by δ- (In the absence of a known surface...
PROBLEM 3 (45 points) The condenser of a large steam power plant is a heat exchanger in which steam is condensed to liquid water. Assume the condenser to be a parallel flow shell-and-tube heat exchanger consisting of a single shell and 1x10 tubes, each executing two passes. The inner diameter of tubes is D = 50 mm and its thickness is 5 mm (Do not ignore the thickness). The steam condenses on their outer surface. Thermal conductivity of the tube...
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