Question

Problem 2: A stainless steel rod (k-21 W/m-K, p-8000 kg/m3, C,,-570 J/kg-K) with diameter D-10 mm is heat-treated as it passeProblem 2 h, Too 2 cm/s 3 m

Problem 2: A stainless steel rod (k-21 W/m-K, p-8000 kg/m3, C,,-570 J/kg-K) with diameter D-10 mm is heat-treated as it passes through a furnace at a speed of 2 cm/s. The furnace has a convection coefficient of 80 W/m2-K and an air temperature of 900°C. The furnace is 3 m long, and the stainless steel enters at 20°C. (a) Using a control volume of length S traveling with the rod, develop a differential equation for the rate of change of the temperature of the control volume (i.e., dT/dt) Can you assume lumped capacitance in the control volume? (b) By solving the differential equation, determine the temperature of the rod when it exits the furnace as it travels through the furnace.
Problem 2 h, Too 2 cm/s 3 m
0 0
Add a comment Improve this question Transcribed image text
Answer #1

vomme 23m Candral T C c 3 m hT8 Yod Steel Stan less leglm3 &o0O D V 2 - 2 Gml( = 0.0 m Ti20c Ya Bi chene J Lc V). = TDL A TBi O 21 less thon +Le bcunenov value abune resitence n 3oel Can be Tntenmal D.1 neg leetedl COrsiden mi nitesy Smali elemend3A -2 ( Tio-T) t0 - hxp h x TD CTe-T) aT ( Toe-T ) = 0 Scp D Hene To-T. do dt SepD dt d o x dt S Cp D 1ntegatn No U (9 4h Sp

(which gie temp. vanile) - T-Tao e Ti-To hene Zvegouk here COnste V2 - v. df findlimy lo an Cuben Lis tanee aj tavels uae jhe

Add a comment
Know the answer?
Add Answer to:
Problem 2: A stainless steel rod (k-21 W/m-K, p-8000 kg/m3, C,,-570 J/kg-K) with diameter D-10 mm is heat-treated as it...
Your Answer:

Post as a guest

Your Name:

What's your source?

Earn Coins

Coins can be redeemed for fabulous gifts.

Not the answer you're looking for? Ask your own homework help question. Our experts will answer your question WITHIN MINUTES for Free.
Similar Homework Help Questions
  • Problem 2. A long 6.5 cm diameter solid cylinder steel (K 16.3 W/m. K,p 7817 kg/m3,...

    Problem 2. A long 6.5 cm diameter solid cylinder steel (K 16.3 W/m. K,p 7817 kg/m3, Cp 460 J/kg.k). It's initially at a uniform temperature of T 150°C. It is suddenly exposed to a convection environment with h-285 W/m2 K and Too 50°C. Calculate the temperature at 1.) the axis of the cylinder, and 2.) a 2.5 cm radial distance after 5 min of exposure to the cooling flow. (20%)

  • A rod of diameter D = 25 mm and thermal conductivity of 60 W/m K protrudes from a furnace with a wall temperature of 200°C.

    A rod of diameter D = 25 mm and thermal conductivity of 60 W/m K protrudes from a furnace with a wall temperature of 200°C. The rod is welded to the furnace wall and is used as a hangar for instrumentation cables. To avoid damaging the cables, the surface temperature of last 100 mm of the rod must be kept below 100°C. The ambient air temperature is 25°C and the convection coefficient is 15 W/m2K. (a) Write the finite-difference equation for...

  • Problem 3 (50 points). A long stainless steel cylinder with diameter of d=55cm is heated up...

    Problem 3 (50 points). A long stainless steel cylinder with diameter of d=55cm is heated up to 450°C. The cylinder is then cooled slowly in a chamber at 150°C with an average convection heat transfer coefficient of h = 70 W/m2.°C. (a) Find the temperature at the center of the cylinder after 25 min. (b) Find the heat transfer per unit length of the cylinder during this time period. Cylinder properties: k=15 W/m•°C, p=8000 kg/m², c=477 J/kg•°C, a=3.95x10-6 m²/s.

  • H8-1: An 8-m-internal-diameter spherical tank made of 1.5-cm-thick stainless steel (k-15 W/m K) i...

    H8-1: An 8-m-internal-diameter spherical tank made of 1.5-cm-thick stainless steel (k-15 W/m K) is used to store iced water at 0°C. The tank is located in a room whose temperature is 25°C. The convection heat transfer coefficients at the inner and the outer surfaces of the tank are 80 W/m2 K and 10 W/m2 K, respectively. Radiatior heat transfer is negligible. Determine the rate of heat transfer to the iced water in the tank. room 25°0c T. Iced water 0...

  • A long steel bar with a diameter of 4 cm (ρ = 7840 kg / m3...

    A long steel bar with a diameter of 4 cm (ρ = 7840 kg / m3 , cp = 580 J / kg ° K, k = 52 W / mK, α = 1.21x10-5 m2 / s), internal enters the 2 m long moving belt heat treatment furnace at ambient temperature of 900 ° C at 40 ° C. Since the film coefficient in the oven is 100 W / m2K, the center axis temperature of the bar at the...

  • A long steel bar of radius R=2.5 cm, k =50 W/(m °C), p= 7800 kg/m), and...

    A long steel bar of radius R=2.5 cm, k =50 W/(m °C), p= 7800 kg/m), and c = 0.5 kJ/(kg. . °C) is to be annealed by cooling slowly from 800.°C to 100.°C in an environment at temperature 50.°C. If the heat transfer coefficient between the environment and the surface of the bars is h = 45 W/(m .°C), determine the time required for the annealing process using lumped system analysis.

  • A long cylinder of diameter D 0.012 m, thermal conductivity k 358 W/(mK), density p -...

    A long cylinder of diameter D 0.012 m, thermal conductivity k 358 W/(mK), density p - 7614 kg/m3, specific heat c 418 J/(kgK) is initially at a uniform temperature of Ti-74°C. The cylinder is suddenly exposed to a gas at T,-18 ℃ The convection coefficient is h -17 W/(m2K). Verify that a lumped capacitance analysis can be used for the transient response of the cylinder temperature. What is the time t in seconds for the cylinder temperature to become Tf-32...

  • A long wire with circular cross section and diameter D = 1 mm is submerged in an oil bath with temperature To 20。C. The wire is initially at temperature T = 20。C, the same temperature as the oil. A...

    A long wire with circular cross section and diameter D = 1 mm is submerged in an oil bath with temperature To 20。C. The wire is initially at temperature T = 20。C, the same temperature as the oil. A current is passed through the wire, resulting in a volumetric heat generation of q - 1.5 x 108 W/m3. The convection coefficient is h - 500 W/m2 - K, and the properties of the wire are ρ-8000 kg/m3, Cp-500 J/kg-K, and...

  • Q2 (a) A 12 mm diameter mild steel sphere (k = 42.5 W/m K) is exposed...

    Q2 (a) A 12 mm diameter mild steel sphere (k = 42.5 W/m K) is exposed to cooling airflow at 27 "C resulting in the convective coefficient, h = 114 W/m' K. The relevant properties of mild steel are given as follows: Density p= 7850 kg/m . Specific heat c = 475 J/kg K and thermal diffusivity a = 0.043 m/hr Determine: (i) Time required to cool the sphere (lumped parameter system) from 540 °C to 95°C. [7 marks] (ii)...

  • QUESTION TWO Carbon steel balls (p 7833 kg/m3, k-54 W/m K, cp 0.465 kJ/kg.0C and a-1.474...

    QUESTION TWO Carbon steel balls (p 7833 kg/m3, k-54 W/m K, cp 0.465 kJ/kg.0C and a-1.474 x 10-6 m2/s) 10 mm in diameter are annealed by heating them first to 900'C in a furnace and then allowing them to cool slowly to 100°C in ambient air at 35°C. If the average heat transfer coefficient is 75 W/m2 K, determine how long the annealing process will take. If 2500 balls are to be annealed per hour, determine the total rate of...

ADVERTISEMENT
Free Homework Help App
Download From Google Play
Scan Your Homework
to Get Instant Free Answers
Need Online Homework Help?
Ask a Question
Get Answers For Free
Most questions answered within 3 hours.
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT