Question

5. A spherical thermocouple bead of diameter D = 0.002 m (i.e. 2 mm) on the tip of a wire is used to measure tempera- ture of a low-speed, hot gas flow in a duct (Fig. 2). The gas' approach speed is U. = 2 m/sec and its respective density and viscosity are p = 1 kg/m3 and v = 2 x 10-5 m2/s. The coefficient of drag for such moderate flows is well- approximated by the curve fit Cp ~ 17.7 Rep0.59 10 < Red 500 , where Rep is the Reynolds number based on diameter. Fig. 2: Thermocouple. (a) (10 pts) Calculate the thermocouple's Cp for this particular flow. 0 0.12 0 3540 403.3 1.3 0.78 0.18 none of these

Answer 1

Solution.. Data given - Bead bia (D)= .002m I gas speed ( Uola amis gas's kinematic viscosityl V520of mine 0 Coefficient of Drag Relation; (* 17.7 (Rey) where: Reg = Reynold's Number Rege person or v = RM205 = 20 using in eg DE 17.7 (200) = .7769 UD 2 x .002 M ass (o=.78] option (5) Auswer