A fluid is flowing through two different tubes of same cross-section area. We are to compare the heat transfer rate in these two tubes over the same length. First tube is circular cross-section and the second one has a square cross-section. The flow is laminar and fully-developed in both cases. The tube surface can be approximated as isothermal in both cases. Also assume that the average temperature difference between the surface and the fluid is approximately the same in both cases. What is the ratio of the heat transfer rates (between the tube and the fluid) between the first and second tube?

A fluid is flowing through two different tubes of same cross-section area. We are to compare the heat transfer rate in these two tubes over the same length. First tube is circular cross-section and the second one has a square cross-section. The flow is laminar and fully-developed in both cases. The tube surface can be approximated as isothermal in both cases. Also assume that the average temperature difference between the surface and the fluid is approximately the same in both cases. What is the ratio of the heat transfer rates (between the tube and the fluid) between the first and second tube?

Elements Of Electromagnetics

7th Edition

ISBN:9780190698614

Author:Sadiku, Matthew N. O.

Publisher:Sadiku, Matthew N. O.

ChapterMA: Math Assessment

Section: Chapter Questions

Problem 1.1MA

See similar textbooks

Similar questions

An electric heater heats the inner tube walls of a concentric tube annulus at a rate of 2000 W/m. The inner and outer tube diameters are 25 and 50 mm respectively. Water enters the annular region at 25 ⁰C and leaves at 85 ⁰C. The flow rate of water is 0.04 kg/s and the outer tube wall is insulated. Assuming that fully developed conditions exist at the outlet, the inner tube surface temperature at the outlet will be ?
Water is to be heated from 35 °C to 65 °C in a rough tube with a relative roughness of 0.001. The tube has an electric heater provides a constant heat flux such that the tube average wall temperature is 20 °C above the average water bulk temperature. The Reynolds number used for calculating the heat-transfer coefficient is 100,000. Calculate the length of tube required for heating, expressed in meters, if the tube has a diameter of 1 cm.
Fluid is flowing through a 20 mm inside diameter and 25 mm outside diameter brass tube at no leaking with temperature at 149oF and length of 10 m. Surface conduction of hot fluid is 5.2 W/m2-K and thermal conductivity of brass is 12.84 W/m2-K. Brass tube is covered by silica of 6 mm thickness with thermal conductivity of 13.84 W/m-K. Outside of it, is a fluid with 45oC with surface conductance of 3.2 W/m2-K. Find the heat transfer from the hot fluid with temperature of 149oF to fluid with temperature of 45oC.
A condenser consists of 5 pieces of 3 m long 1/4 in Sch 40 horizontal pipes lined up in 6 rows. It transfers cooling water with a heat transfer coefficient of 2000 W / m-K through the pipes. As the flow rate of the water is very high, the water temperature is constant at 35 degrees Celsius. Saturated heat vapor condenses at a pressure of 2 bars outside the pipes. Calculate the condenser capacity in kW
4. For a thermally fully developed flow in a pipe for a fluid with constant properties, the local convection coefficient (a) Decreases as x-1/2 (b) Decreases as x-1/5 (c) Increase as x1/2 (d) Increases as x4/5 (e) Remains constant
An electric resistance heater is embedded in a long cylinder ofdiameter 30mm. When water with a temperature of 25 C and velocityof 1m/s flows crosswise over the cylinder, the power per unit lengthrequired to maintain the surface at a uniform temperature of 90 C is28kW/m. When air, also at 25 C, but with a velocity of 10m/s isflowing, the power per unit length required to maintain the samesurface temperature is 400W/m. Calculate and compare the convectioncoefficients for the flows of water and air.
A cube is being cooled within a tube that has air being pushed by a fan. The heat transfer coefficient (h) for the cube is lower when it is at the center of the tube, and higher when it is at the edges (resulting in a concave up parabola when it is plotted against the position). Why does this occur?
Harry up plz
PLEASE ANSWER WITH DETAILED STEPS AND EXPLANATION. THANKS ?
Calculate the heat flow per square meter (heat flux) through water medium with thermal conductivity of 0.6, flowing in a 5 cm thickness space, if the temperatures on the two surfaces are 50 and 210°C, respectively.
Consider an engineer calculating the heat transfer laminar forced convection in a 2-m long rectangular tube. Flow becomes fully developed after 1 m. If the engineer uses a heat transfer coefficient for fully developed flow, the heat transfer rate calculated is
A Figure illustrates the tube-flow system. The heat transfer under developed flow conditions when the flow remains laminar. The wall temperature is Tw, the center of the tube temperature is Te the radius of the tube is re, and the velocity at the center of the tube is uo. The velocity distribution equation is: 1 uo Prove that: 1 aT uor. T - T= a ax 4 ro Start the solution of the equation : P{żar drjuc,T 1 a ()- aT 1 әт ur дr ar « дх