Question

In many cookbooks, it is stated that a slab of steak, roasted in a convection oven, is considered "well-done" when the center-line temperature of the slab reaches 80 °C. A slab of steak is initially at 6 °C before it is placed in the oven, in which the ambient air temperature is 175 °C. The mean convective heat transfer coefficient between the slab of steak and the air inside the oven 15 W/(m2.K) Approximate the slab of steak as a SHORT CYLINDER, with its thickness equal to its diameter For the steak, use the following material properties: k 0.634 W/(m.K); p 991 kg/m2; C= 4179 J / ( kg .K) Using the HEISLER CHART METHOD, calculate how long it will take to cook a slab of steak, having a mass of 2.25 kg, to "well-done" state. NOTE: SOLUTION OF THIS PROBLEM INVOLVES TRIAL-AND-ERROR.

Answer 1

(ida) Gwan, fos a slab o steak 2.25 mas iametes -thickrass o. 624 W/k 991 4179 mean haat tanshA Coeicent h= t5 cantre line temp. So°c Initial temp, T = Ambient tamp, 75 C o.634 Theraval iust, 491(4119 IS.3 x lo M=ex volume we tnouo 991 x TT d 2.25 O.Iy2y M adius, O.o712 m hs goot Numb, B IS (o.0112) o.634 Bi .68S

o.5935 Bi Temp. Distibubior, o-T Q8-SL = o.562 Foom Heis lo cht fouies Numb Fe o.G = o. 6 IS.3x1o ニo、6 0712) 2 Lime taten Cook, t the Slab o Staak 七= 5.52 hy.

Figure 4: Temper ature distribution in a cylin der at center line 100'0 000 00Z0S OEI SII 00106 08 04 09 09 00 80 90 022 0281 91IZ1 OI 8 9 Z00'0 000 TOO 700 FOO O'C 7 Bi=k/hro 2.5 3.0 6.6 3.5 E'O 9 8 001-