In steel processing industry, structural steel products are fabricated by heating, rolling and then cooling process....
Fantastic news! We've Found the answer you've been seeking!
Question:
Transcribed Image Text:
In steel processing industry, structural steel products are fabricated by heating, rolling and then cooling process. A steel rod of cylindrical shape is at the uniform temperature of 900°C at the end of the rolling process, is then placed in a cooling bed to lower its temperature. Assume the rod diameter is D = 40 mm and the length is L = 100 m. During the cooling process, due to the phase transformation inside the steel (such as austenite to perlite), heat is generated internally at the uniform rate of 4 = 5 x 105 W/m3 when the steel temperature is in the range of 900°C to 650°C; while the internal heat generation rate vanishes for the steel temperature below 650°C. Although the steel properties vary as the temperature is lowered, constant values may be assumed reasonably with density p = 7832 kg/m³, specific heat at constant pressure Cp = 600 J/kg.K and the thermal conductivity k = 50 W/m.K. The cooling is provided by natural convection of the room air and radiation to the surrounding with a combined heat transfer coefficient of h = 100 W/m2.K. a) Determine the time required for the steel rod to reach the final temperature Tf = 200°C, if the room air temperature is maintained at To = 30°C. b) In order to shorten the cooling time, it is proposed to switch to forced convection cooling (with a heat transfer coefficient of h = 5000 W/m2.K) after the steel temperature reaches to 650°C. How much decrease in cooling time can be achieved by doing this? %3D In steel processing industry, structural steel products are fabricated by heating, rolling and then cooling process. A steel rod of cylindrical shape is at the uniform temperature of 900°C at the end of the rolling process, is then placed in a cooling bed to lower its temperature. Assume the rod diameter is D = 40 mm and the length is L = 100 m. During the cooling process, due to the phase transformation inside the steel (such as austenite to perlite), heat is generated internally at the uniform rate of 4 = 5 x 105 W/m3 when the steel temperature is in the range of 900°C to 650°C; while the internal heat generation rate vanishes for the steel temperature below 650°C. Although the steel properties vary as the temperature is lowered, constant values may be assumed reasonably with density p = 7832 kg/m³, specific heat at constant pressure Cp = 600 J/kg.K and the thermal conductivity k = 50 W/m.K. The cooling is provided by natural convection of the room air and radiation to the surrounding with a combined heat transfer coefficient of h = 100 W/m2.K. a) Determine the time required for the steel rod to reach the final temperature Tf = 200°C, if the room air temperature is maintained at To = 30°C. b) In order to shorten the cooling time, it is proposed to switch to forced convection cooling (with a heat transfer coefficient of h = 5000 W/m2.K) after the steel temperature reaches to 650°C. How much decrease in cooling time can be achieved by doing this? %3D
Expert Answer:
Related Book For
Vector Mechanics for Engineers Statics and Dynamics
ISBN: 978-0073212227
8th Edition
Authors: Ferdinand Beer, E. Russell Johnston, Jr., Elliot Eisenberg, William Clausen, David Mazurek, Phillip Cornwell
Posted Date:
Students also viewed these chemical engineering questions
-
You are planning a multi-day backpacking hiking trip with two of your friends to Wells Gray Provincial park, a remote provincial park in British Columbia known for its dozens of grand, majestic...
-
A slender, uniform steel rod of length 9 in. is placed inside a pipe as shown. Knowing that the coefficient of static friction between the rod and the pipe is 0.20, determine the largest value of...
-
A uniform slender rod of length h L = 900 mm and mass m = 1 kg hangs freely from a hinge at A. If a force P of magnitude 3.5 N is applied at B horizontally to the left (h = L), determine (a) The...
-
Rafael Espinal's leadership approach is best categorized as what type of leadership? spiritual adaptive authentic servant
-
What is a complete liquidation? A partial liquidation? Explain the difference in the tax treatment accorded these two different events.
-
Which U.S. government agency regularly publishes alerts and bulletins related to security threats? A. NIST B. FBI C. US-CERT D. MITRE Corporation
-
Research whether there are any ethics opinions in your state that concern the use of social media. Are there any court cases?
-
Determine the force in members BC, HC, and HG. After the truss is sectioned use a single equation of equilibrium for the calculation of each force. State if these members are in tension or...
-
3. [-/2 Points] DETAILS LCALCCON5 3.5.011. Consider the following. g(x) = 8x24; h(x) = 1.9x (a) Write the product function. f(x) = (b) Write the rate-of-change function. f'(x) =
-
Walmart makes significant investments in operating capacity, primarily via investments in property, plant, and equipment, but also via investments in wholly and partially owned subsidiaries. Walmart...
-
ABC are three partners sharing profit and loss equally. B retires from the firm and his share of profit was purchased by A and C in the ratio 2:1. Find the gaining ratio of A and C.
-
Design your reports to aid in decision making.
-
Name and describe key categories of business etiquette in the intercultural communication process.
-
Explain how to handle emotion effectively in online communications.
-
Demonstrate excellent thinking by applying a precision-oriented style to reports.
-
Describe and demonstrate effective questions for enhancing listening and learning.
-
A certain message exchange system only enables the use of the 26 uppercase Roman letters, without any spaces, punctuation, or special characters. The letters A through Z take numerical values in...
-
l ask this second time correnct answer is 38,01 can we look pls Consider a non-conducting rod of length 8.8 m having a uniform charge density 4.5 nC/m. Find the electric potential at P, a...
-
Knowing that at the instant shown the angular velocity of rod BE is 4 rad/s counterclockwise, determine (a) The angular velocity of rod AD, (b) The velocity of collar D, (c) The velocity of point A....
-
The steel plate shown supports six 2-in. diameter idler rollers mounted on the plate as shown. Two flat belts pass around the rollers, and rollers A and D are adjusted so that the tension in each...
-
Rod AB moves over a small wheel at C while end A moves to the right with a constant velocity vA. Using the method of Sec. 15.9, derive expressions for the angular velocity and angular acceleration of...
-
A Ltd owns 100% of the issued share capital of B Ltd and 70% of the issued share capital of C Ltd. C Ltd owns 70% of the issued share capital of D Ltd. (a) Which companies are associated with A Ltd?...
-
S1 Ltd and S2 Ltd belong to the same capital gains group. In May 2020, S1 Ltd transferred a chargeable asset to S2 Ltd. The original cost of this asset to S1 Ltd was 10,000 and its market value in...
-
The ordinary share capital of W Ltd (which is a trading company) is owned 30% by X Ltd, 25% by Y Ltd and 45% by Z Ltd. All of these companies are UK resident and they prepare accounts to 31 March....
Study smarter with the SolutionInn App