If forced convection uses Reynolds number to account for fluid movement during forced convection, what dimensionless number is used for natural convection?
Q: During a high Reynolds number experiment, the total drag force acting on a spherical body of…
A: Given data, From stokes equation,
Q: Air at 1 atm is flowing at a velocity of 2.2 m/s across a flat plate. The film temperature between…
A: Given data: Pressure of air = P = 1 atm Velocity of air = V = 2.2 m/s Film temperature between the…
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A: Convection is the circular motion that occurs when warmer air or liquid rises, while colder air or…
Q: Air at 20oC and 1 atm flows over a flat plate at 35 m/s. The plate is 75 cm long and 100 cm depth…
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Q: Which of the following statement is wnong? O a. In the boundary layer region the frictional effect…
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Q: Q5) Air at -10°C flows over a flat surface at 10°C with a free stream velocity of 80 m/s. The length…
A: given data air temperature = -10°C air speed = 80 m/s surface temperature = 10 °C length of plate =…
Q: Engine oil at 80°C flows over a flat surface at 40°C for cooling purpose, the flow velocity being 2…
A: Given Velocity, v = 2 m/s Distance, x = 0.4 m Properties at 80 + 40 /2 = 60oC Kinematic…
Q: Define Nusselt (Nu), Prandtl (Pr), Reynolds (Re) and Grashof (Gr) dimensionless numbers. State which…
A: Nusselt number represents the enhancement of heat transfer through a fluid layer as a result of…
Q: The Nusselt number is a kind of dimensionless number which is a function of convective heat transfer…
A: Nusselt number is the dimension less quantity which is the function of Reynolds number and Prandtl…
Q: A 10-cm-diameter and 10-m-long cylinder with a surface temperature of 10°C is placed horizontally in…
A: Given : The ambient temperature = 40 °C The surface temperature of the cylinder = 10 °C The diameter…
Q: 60°C glycerin flows over a 15m long flat plate with temperature of 20°C. The velocity of glycerin is…
A: Prandtl number is the only dimensionless number that is the property of the fluid. It is defined as…
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Q: A long, 20-cm diameter pipe is carrying hot water. The temperature of the air around the pipe is…
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Q: Hot water is being transported in a horizontal pipe (k = 0.15 W/m∙K, Di = 2.5 cm, Do = 4.5 cm),…
A: Given data Thermal conductivity of the pipe = 0.15W/mK Inner dia of pipe Di = 2.5 cm = 0.025m ri=…
Q: In thermally fully developed flow of a fluid with constant properties, the local convection…
A: Thermally fully developed flow of fluid is in which temperature profile doesn't change along the…
Q: 1. The dimensionless A. Prandtl number number not used in forced convection is: B. Reynolds number…
A: Note: Since you have asked multiple question, we will solve the first question for you. If you want…
Q: Write a short note on significance of various dimensionless numbers in heat transfer.
A: Heat transfer: According to thermodynamics law's, heat can be transfer from one part to another .…
Q: For external forced convection with an isothermal surface, what is the Nu# correlation equation for…
A: Nusselt number (Nu) signifies the ratio of conductive resistance to the convective resistance…
Q: A) Among the nondimensional numbers, in free convection, average Nusselt number depends on only…
A: (A) Free convection, in free convection the heat transfer takes place due to density difference. now…
Q: One of the non-dimensional number is important to determine whether forced convection is important…
A: If Grashof number (Gr.) is, Gr. > 109 Forced convocation dominant. Gr. < 109 Natural…
Q: Q2) Air at 20°C and 1 atm flows over a flat plate at 35 m/s. The plate is 75 cm long and 100 cm…
A: Given: The temperature of air, T = 20°C The pressure of air, P = 1 atm The velocity of air, v = 35…
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Q: A 25-cm circular grill has an emissivity of 0.9. The temperature of the air and surrounding surfaces…
A: To determine the heat transfer from the grill, first of all we need to determine the Reynold number…
Q: Relationship between fluid flow and convection heat transfer
A: The motion of the fluid subjected to the unbalanced forces is called as fluid flow. As long as the…
Q: Volumetric thermal expansion is used in modeling natural convection heat transfer. Derive an…
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Q: 3. (a) Discuss, the concepts of velocity boundary layer and temperature boundary layer. Provide some…
A: Velocity Boundary Layer; when a fluid flows over a stationary surface, e.g. the flat plate, the bed…
Q: What is the rate of heat loss through a 4-cm Fiberglass wall of the inside temperature is 22 °C and…
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Q: A circular plate of diameter (1.36 m) is placed some how 1.5 meter above the room floor, if the…
A: Solution:
Q: A large vertical plate 6.1 m high and 1.22 m wide is maintained at a constant temperature of 57+C…
A: Determine the mean film temperature
Q: A spherical block of dry ice at -79°C is exposed to atmospheric air at 30°C. The general direction…
A: The direction is explained with the concept of natural convection
Q: Water at 45.0oC flows over a large plate at a velocity of 30.0 cm/s. The plate is 1.0 m long (in the…
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Q: Differentiate between free and forced convection with examples.
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Q: Air at 1 atm is flowing at a velocity of 1.5 m/s across a flat plate. The film temperature between…
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Q: During flow over a given body, the drag force, the upstream velocity, and the fluid density are…
A: Drag force is the resistive force exerted by a fluid due to its motion. Drag force is supposed to…
Q: A fluid of density 1200 kg/m° at 1 atm pressure is compressed to 101 atm pressure isothermally. If…
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Q: Air at 25 ° C blows over the hot steel plate whose surface temperature is maintained at 150 ° C. The…
A: Given data: The temperature of the air is T∞=25°C The surface temperature of the plate is Ts=150°C…
Q: Prove that by using dimensional analysis Nusselt number is a function of Reynolds number and Prandtl…
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Q: Question 7 In the case of natural convection over a vertical hot wall, at boundary layer thickness…
A: Answer: The correct answer is option (c).
Q: One of the non-dimensional number is important to determine whether forced convection is important…
A: With the help of Reynolds no. And grashofs no. It is easy to determine whether forced convection is…
Q: In flow over a surface, velocity and temperature profiles are of the forms u(y) = Ay + By? + Cy3 and…
A: Note- due to company policy i can provide you only one answer if you want to answer outher…
Q: One of the non-dimensional number is important to determine whether forced convection is important…
A: The Rayleigh number is a non-dimensional which is equal to the product of Grashof number and Prandtl…
Q: 4. For a flat plate, the transition from the free convection boundary layer to the free convection…
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Q: Air at 200C flowing at 25 m/s passes over a flat plate, the surface of which is maintained at 270°C.…
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Q: Q3/Air at 0.5 atm pressure and 27 C flows across a 34-cm-square plate at a velocity of 20 m/s. The…
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Q: 1. Which is more effective in transferring heat by natural convection or forced convection?
A: In convection mode of heat transfer, heat transfer takes place by moving molecules or atoms of…
Q: Q2/Engine oil at 80°C flows over a 6-m-long flat plate whose temperature is 30°C with a velocity of…
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Q: In experimental aerodynamics, what is the difference between time-averaged and time- resolved…
A: The open cavity is characterized by a mixing layer at the cavity top, that divides the flow field…
Q: A 20degC water flows to 50cmx60cm flat plate with velocity of 5.2m/s . The flat plate surface…
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- A fluid (Prandtl number, Pr = 1) at 500 K flows over a flat plate of 1.5 m length, maintained at 300 K. The velocity of the fluid is 10 m/s. Assuming kinematic viscosity, v = 30 × 10 layer thickness (in mm) at 0.5 m from the leading edge is – 6 m2/s, the thermal boundaryFor laminar free convection flow on a vertical plate, a popular correlation 1/4 is Nu, = CRa,*. Derive the values of C from the similarity solution. for Pr = 0.01, 1, 10, and 100. %3D Nu, = hL. = C Ra k (9.24) gB(T, – T)L³ va Ra = Gri Pr = (9.25) 4 GrL 1/4 hL Nu k 8(Pr) %3D 4 0.75Pr2 (0.609 + 1.221Pr2 + 1.238Pr)4 g(Pr) (9.20) 4/3A Deep-sea Diver is wearing a wetsuit in cold water. (Natural convection, radiative transfer is negligible). The following data are given: Water Temperature Te= 10 Degrees Celsius. Wetsuit thickness is equivalent to a 8mm neoprene rubber (thermal conductivity is 0.19 W/m-K), Skin thickness is 1.45mm, Skin thermal conductivity is 0.21 W/m-k. Body temperature below skin Tb= 37 degrees Celsius. Average Air gap thickness is 1mm, air thermal conductivity = 0.027 w/m-K. a) Draw a complete equivalent thermal circuit and show all parameters. b) Calculate the flux of heat loss from the diver (in W/m^2 of body surface area) c) Calculate the temperature of the skin outer surface (Ts) d) Based on your calculations is the wetsuit adequate to keep the diver warm enough? Why?
- Consider a diatomic gas at temperatures T1 and T2 such that r = kyT;le = 0.30 and 12 = 0.32 for the gas's rotational energy storage mode. (a) Evaluate the partition function directly as a sum for each temperature, keeping what you think is a sufficient number of terms needed to ensure six significant figures of accuracy. Z for T:[ Zfor T2: (b) For T1 and T2, compute Eg = E Pr(E)E (in terms of e) directly as a sum with the same number of terms. Eavg for T: Eavg for T2: (c) Note that dEwldr [Eave (12) - Eav (T))/[r - ] as long as r - is sufficiently small. Use this approximation to estimate the value of r dE at r0.31. Estimate for dEn Compare your result with the figure shown below. Are you close? (You should bel) he de (dEavg/dT)/kg for rotation 1.2 1.0 0.8 0.6 0.4 0.2 0.0how to quickly recognize isothermal boundary condition. and in case of isothermal boundary conditions, sometimes its writtens as T=To and sometimes written dT/dx=0 which one to apply?..P15 A horizontal cylinder 10 cm in diameter contains helium gas at room temperature and atmospheric pressure. A piston keeps the gas inside a region of the cylinder 20 cm long. (a) If you quickly pull the piston outward a distance of 12 cm, what is the approximate temperature of the helium immediately afterward? What approximations did you make? (b) How much work did you do, including sign? (Note that you need to consider the outside air as well as the inside helium in calculating the amount of work you do.) (c) Immediately after the pull, what force must you exert on the piston to hold it in position (with the helium enclosed in a volume that is 20 + 12 = 32 cm long)? (d) You wait while the helium slowly returns to room temperature, maintaining the piston at its current location. After this wait, what force must you exert to hold the piston in position? (e) Next, you very slowly allow the piston to move back into the cylinder, stopping when the region of helium gas is 25 cm long.…
- Example(1-14): mixture gas and liquid flow through 0.02 m inside diameter pipe at total flow rate of 0.2 kg/s. if the gas weight fraction is 0.149 what is the pressure drop per unit length of pipe. Where the pipe roughness 0.00015 mm, liquid and gas viscosities are 2x103 pa.s and 1x10-5 pa.s respectively. finaly the liquid and gas densities are 1000 kg/m³ and 60 kg/m³ pa.s respectively.(d) Why is it important when assessing indoor air quality to re-establish the parameters of the turbulence model as used in a CFD simulation at each time step? In your answer identify these parameters.Consider a thin-walled, fi xed-volume container of volume V that holds an ideal gas at constant temperature T. It can be shown by dimensional analysis that the number of particles striking the walls of the container per unit area per unit time is given by nv-/4, where as usual n is the particle number density. The container has a small hole of area A in its surface through which the gas can leak slowly. Assume that A is much less than the surface area of the container. (a) Assuming that the pressure inside the container is much greater than the outside pressure (so that no gas will leak from the outside back in), estimate the time it will take for the pressure inside to drop to half the initial value. Your answer should contain A, V, and the mean molecular speed v-. (b) Obtain a numerical result for a spherical container with a diameter of 40 cm containing air at 293 K, if there is a circular hole of diameter 1.0 mm in the surface.
- Topic: Heat transfer Completely solve and box the final answer. 1. A 20degC water flows to 50cmx60cm flat plate with velocity of 5.2m/s . The flat plate surface temperature is maintained at 40deg C. The air flows parallel to the 50cm side of the plate. If the kinematic viscosity of water is 78x10-8 m2/s, at what length the flow become turbulent?Water at a temperature of T∞= 25°C flows over one of the surfaces of a steel wall (AISI 1010) whose temperatures Ts,1= 40°C and thermal conductivity of steel is 671 w/m.k. The wall is 0.35 m thick, and its other surface temperature is Ts,2= 100°C. For steady state conditions what is the convection coefficient associated with the water flow?HEAT TRANSFER From the heat transfer property table of water, the properties at 20 0C are as follows: Density = 997.36 kg/m3 Kinematic viscosity = 1.026 × 10-6 m2/s Prandtl number = 7.17 (i) Thickness of hydrodynamic boundary layer = 9.24 mm (ii) Thickness of thermal boundary layer = 4.79 mm (iii)Local friction coefficient = 0.001228 Average friction coefficient = 0.002456 ANSWER QUESTION (iv) ,(vi) and B