Related MCQs

• Time lag is given by the formula
• Consider he above problem, find the rate of change of temperature at the inside surface of the tube
• At a certain time instant, the temperature distribution in a long cylindrical fire tube can be represented approximately by the relationT = 650 + 800 r – 4250 r2Where temperature t is in degree Celsius and radius r is in meter. Find the rate of heat flow such that the tube measures: inside radius 25 cm, outside radius 40 cm and length 1.5 m.For the tube materialK = 5.5 W/m Kα = 0.004 m2/hr
• A large plane wall, 40 cm thick and 8 m2 area, is heated from one side and temperature distribution at a certain time instant is approximately prescribed by the relationT = 80 – 60 x +12 x2 + 25 x3 – 20 x4Where temperature t is in degree Celsius and the distance x in meters. Make calculations for heat energy stored in the wall in unit time.For wall material:Thermal conductivity = 6 W/m K and thermal diffusivity = 0.02 m2/hr.
• The temperature distribution at a certain time instant through a 50 cm thick wall is prescribed by the relationT = 300 – 500 x – 100 x2 + 140 x3Where temperature t is in degree Celsius and the distance x in meters has been measured from the hot surface. If thermal conductivity of the wall material is 20 k J/m hr degree, calculate the heat energy stored per unit area of the wall
• A single cylinder 2-stroke engine operates at 1500 rpm. Calculate the depth where the temperature wave due to variation in cylinder is damped to 1% of its surface value. For the cylinder material, thermal diffusivity = 0.042 m2/hr
• The temperature variation of a thick brick wall during periodic heating or cooling follows a sinusoidal waveform. During a period of 24 hours, the surface temperature ranges from 25 degree Celsius to 75 degree Celsius. Workout the time lag of the temperature wave corresponding to a point located at 25 cm from the wall surface. Thermo-physical properties of the wall material are; thermal conductivity = 0.62 W/m K; specific heat = 450 J/kg K and density = 1620 kg/m3
• TIME_LAG_IS_GIVEN_BY_THE_FORMULA?$
• CONSIDER_HE_ABOVE_PROBLEM,_FIND_THE_RATE_OF_CHANGE_OF_TEMPERATURE_AT_THE_INSIDE_SURFACE_OF_THE_TUBE?$
• Consider the above problem, calculate rate of temperature change at 20 cm distance from the side being heated