.5 cm, respectively. The pipe is covered with 3-cm-thick glass wool insulation (k = 0.038 W/m⋅K). Heat is lost to the surroundings at 5° C by natural convection and radiation, with a combined natural convection and radiation heat transfer coefficient of 22 W/ m2⋅K.Taking the heat transfer coefficient inside the pipe to be 80 W/ m2⋅K.Determine the rate of heat loss from the steam per unit length of the pipe and Determine the temperature decrease between the inner pipe surface and the outer i

400 circumferential fins of rectangular profile (k = 386 W/m °C) are installed on a tube having a diameter of 3 cm and 1 m length that is maintained at a temperature of 200°C. The single fin has a length of 2 cm and a thickness of 0.7 mm. The heat is transferred to the surrounding air at 100°C with a convection heat-transfer coefficient of 524 W/m2 °C. How many times is the heat transfer rate enhanced when the fins are installed on the tube?

A pipe 30 m long with an outer diameter of 75 mm is used to deliver steam at a rate of 1500 kg / hour. The steam pressure is 198.53 kPa entering the pipe with a quality of 98%. The pipe that needs to be insulated with a thermal conductivity of 0.2 W / (m K) so that the quality of the steam only decreases slightly to 95%. The temperature of the outer surface of the insulation is assumed to be 25 ° C. The conductive of the pipe material and the situation of no pressure drop in the pipe.        A. Determine the enthalpy of incoming vapor = Answer     kJ / kg.        b. Determine the enthalpy of steam that comes out = Answer     kJ / kg.        c. Determine the change / loss of steam heat along the flow = Answer     watt.        d. Determine the minimum required insulation thickness = Answer     cm.

Water vapor at a temperature of 120 ° C flows through a stainless steel pipe (k = 57 W / mK). The inner diameter of the pipe is 47 mm, the outer diameter is 50 mm, and the length is 100 m. The heat transfer coefficient between the water vapor and the pipe wall is 200 W / m²K, and the heat transfer coefficient between the outer surface of the pipe and the ambient air is 25 W / m_K. The outdoor air temperature is 10 ° C. Find the thermal conductivity coefficient of the insulation material, since it is desired to insulate with an insulation material with a layer thickness of 50 mm in order to reduce the loss of heat from the pipe by 60%.

Liquid flows in a metal pipe with an inner diameter of D1 = 20 mm and an outer diameter of D2 = 30 mm. The thermal conductivity of the pipe wall is 10 W/m⋅K. The inner surface of the pipe is coated with a thin polyvinylidene chloride (PVDC) lining. Along a length of 95 cm, the pipe outer surface is exposed to convection heat transfer with hot gas, at T∞ = 95° C and h = 6 W/m2 ⋅K, and thermal radiation with a surrounding at Tsurr = 95° C. The emissivity at the pipe outer surface is 0.3. The liquid flowing inside the pipe has a convection heat transfer coefficient of 52 W/m2⋅K. If the outer surface of the pipe is at 86° C, determine the temperature at the PVDC lining and the temperature of the liquid.The ASME Code for Process Piping (ASME B31.3-2014, A323) recommends a maximum temperature for PVDC lining to be 81° C. Does the PVDC lining comply with the recommendation of the code?

A plane wall is a composite of two materials, A and B. The wall of material A has uniform heat generation qG = 1.5 × 106W/m3, kA = 75 W/m⋅K, and thickness LA = 50mm. The wall material B has no generation with kB = 150 W/m⋅K and thickness LB = 20mm. The inner surface of material A is well insulated, while the outer surface of material B is cooled by a water stream with T∞ = 30°C and h = 1000 W/(m2⋅K). a. Sketch the temperature distribution that exists in the composite under steady-state conditions. b. Determine the temperature of the insulated surface and the temperature of the cooled surface.

The temperature of a gas stream is measured by a thermocouple whose junction can be approximated as a 1-mm-diameter sphere. Take the junction’s properties as: k of 32 W/m K, density of 8.2 kg/m^3, c of 300 J/Kg K. On its surface, the overall heat transfer coefficient is 200 W/m^2 K. Neglect any conduction loss from the sphere to other parts of the thermocouple. Create a plot of measurement error as a function of time for the thermocouple,  expressed as a fraction of the initial temperature difference.