Chemical Engineering Question

Problem 3 A steel pipe carrying steam has an outside diameter of 89 mm. It is lagged with 76 mm of insulation having an average k = 0.043 W/m - K. Two thermocouples, one located at the interface between the pipe wall and the insulation and the other at the outer surface of the insulation, give temperatures of 115°C and 32°C, respectively. Calculate the heat loss in W per m of pipe.

Liquid food is heated in a tubular heat exchanger. The inner pipe wall temperature is 110 ° C. The internal diameter of the pipe is 40 mm. Product flows at 0.7 kg / s. If the initial temperature of the product is 7 ° C, calculate the convective heat transfer coefficient. The thermal properties of the product are as follows: specific heat = 3.7 kJ / (kg ° C), thermal conductivity = 0.6 W / (m ° C), product viscosity = 500 x 10-6 Pa s, density = 1000 kg / m³ , the product viscosity at 110 ° C = 410 x 10-6 Pa s. a. Find the Reynold number = Answer. b. Find the number Prantl = Answer. c. Find the Nuselt = Answer number d. Convection coefficient = AnswerW / m² ° C.

5. Ametal-clad heating element is of 8 mm diameter and of emissivity 0.95. The element is horizontally immersed in a water bath. The surface temperature of the metal is 260°C under steady state boiling conditions. Calculate the power dissipation per unit length for the heater if water is exposed to atmo- spheric pressure and is at uniform temperature. 1.75 kW/m]

Water flows through a pipe at an average temperature of 7-50°C. The inner and outer radii of the pipe are r,6 cm and ry - 6.5 cm, respectively. The outer surface of the pipe is wrapped with a thin electric heater that consumes 300 W per m length of the pipe. The exposed surface of the heater is heavily insulated so that the entire heat generated in the heater is transferred to the pipe. Heat is transferred from the inner surface of the pipe to the water by convection with a heat transfer coefficient of h55 W/m2 °C. Assuming constant thermal conductivity and one-dimensional heat transfer, express the mathematical formulation (the differential equation and the boundary conditions) of the heat conduction in the pipe during steady operation. Do not solve.. 2 5:46

Q. For case 3(The end of the fin is insulated). Prove that fin efficiency is equal to VHPKA 0 tanh mL tanh mL mL

Answer immediately pls

A steam pipe with 80 mm diameter passes through a room at 25°C (both air and walls). The pipe is painted to white and its surface temperature is 180°C. Determine the total rate of heat loss from the surface per unit length of pipe, if the convective heat transfer coefficient is 15 W/m2⋅K.

A rubber insulated copper wire 2 mm diameter is carrying electric current and exposed to a uniform temperature of air at 40°C. What will be the maximum steady current in amperes that can be allowed if the rubber insulation is not to get heated above 45°C? Insulation thickness=1 mm Thermal conductivity of rubber= 0.15 W/m-K Air film coefficient= 10 W/m2-K Electrical resistivity of copper=10-7 ohm-m A 10.45 A В 2.1 A C) 14.5 A D 4.25 A E 9.65 A F None of these

Q2/ Lubricating oil at 150 "C flows through a 25 m long stainless steel pipe surrounded by a 25 "C air. Calculate the heat flow through the pipe. Knowing that the outer and inner diameters of the pipe are 55 mm and 50 mm respectively, the heat conductivity of the steel is 30 W/m.K, and the heat transfer coefficients of water and air are 3500 W/m.K and 200 W/m.K respectively.