A1.27 cm diameter copper sphere is heated in an convection furnace for a very long time, so that its temperature becomes equal to the temperature (t=260c) of the air in the furnace. then, the sphere is removed from the furnace and is placed in a forced convection flow where the heat transfer coefficient h=17 w/(m^2-°c) and where the temperature is 38 oc. the sphere is allowed to remain in the flow for 7.5 minutes, at which time it is returned to the convection furnace. after 15 minutes in the furnace, the temperature of the sphere is 240.5 °c. find: (a) what is the temperature of the sphere just before it is returned to the furnace? (b) what is the convective heat transfer coefficient of the furnace?

Amass of m 1.5 kg of steam is contained in a closed rigid container. initially the pressure and temperature of the steam are: p 1.5 mpa and t 240°c (superheated state), respectively. then the temperature drops to t2= 100°c as the result of heat transfer to the surroundings. determine: a) quality of the steam at the end of the process, b) heat transfer with the surroundings. for: p1.5 mpa and t 240°c: enthalpy of superheated vapour is 2900 kj/kg, specific volume of superheated vapour is 0. 1483 m/kg, while for t 100°c: enthalpy of saturated liquid water is 419kj/kg, specific volume of saturated liquid water is 0.001043m/kg, enthalpy of saturated vapour is 2676 kj/kg, specific volume of saturated vapour is 1.672 m/kg and pressure is 0.1 mpa.

Two technicians are discussing the intake air temperature (iat) sensor. technician a says that the computer uses the iat sensor as a backup to the engine coolant temperature (ect) sensor. technician b says that the powertrain control module (pcm) will subtract the calculated amount of fuel if the air measures hot. who is correct

Refrigerant 134a enters an insulated compressor operating at steady state as saturated vapor at -26°c with a volumetric flow rate of 0.18 m3/s. refrigerant exits at 9 bar, 70°c. changes in kinetic and potential energy from inlet to exit can be ignored. determine the volumetric flow rate at the exit, in m3/s, and the compressor power, in kw.