Exp.No: Date: THERMAL CONDUCTIVITY OF PIPE INSULATION USING LAGGED PIPE APPARATUS AIM: 1.To determine the heat flow rate through the lagged pipe and compare it with the heater input for known valve of thermal conductivity of lagging material. 2. To determine the approximate thermal conductivity of lagging material by assuming the heater input to be the heat flow rate through lagged pipe. APPARATUS REQUIRED: 1. Ammeter 2. Voltmeter 3. Thermocouple 4. Temperature indicator SPECIFICATIONS: 1. Heater diameter, 2. Heater with asbestos diameter, 4. Length, FORMULA USED: d1 = 20mm d2 = 40mm L = 500mm 3. Heater with asbestos + sawdust diameter, d3 = 80mm Where, Q – Heat transfer rate, watts K1 – Thermal conductivity of asbestos in W/mK K2 – Thermal conductivity of sawdust in W/mK L – Length of the pipe, 0. 5 m ΔT– Temperature difference in K r1 – Heater radius, 0.01m r2 – Heater with asbestos, 0.02m r3 – Radius with asbestos and sawdust, 0.04m sawdust is filled. Heat is transferred through insulation by conduction. ΔT = T (Asbestos) – T (Sawdust) Theory: The insulation is defined as a material which retards the heat flow with reasonable effectiveness. The apparatus consisting of a rod heater with asbestos lagging. Between the asbestos lagging and MS pipe. assembly is inside an MS pipe. convection and radiation or by the combination of these three. There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.Thermal conductivity of asbestos (K1) Where. ΔT = T (Heater) – T (Asbestos) Thermal conductivity of sawdust (K2) Where. The . The experimental set-up in which the heat is transferred through insulation by conduction is understudy in the given apparatus. Calculate K1 (Thermal conductivity of asbestos) and K2 (Thermal conductivity of asbestos). Connect the three pin plug to the 230 v. Allow the unit to attain the steady state condition. 7. These values are noted in the table. 50 Hz. Repeat the experiment from step 2 to step 6 by varying the heat input to the system. 6. 5. heater. Turn the Dimmer stat knob clockwise. 4. temperatures the T 1 represents temperature of temperature T2 represents asbestos and T3 represents the temperature of the sawdust lagging by using the multipoint digital temperature indicator. 3. by using the given formula and note the value in the table. 2. 15 amps main supply and switch on the unit.PROCEDURE: 1. set the heat input by fixing the voltmeter and ammeter readings and note down the heat input Q in the table. temperature of the indicator. When In the the steady state condition the is reached note down the the the temperature indicated by the temperature indicators. . TABLE: Voltmeter Readings Volts S.No V 1 Ammeter Readings Amps I Q=V x I He ater Temp ˚C T1 Asbestos Temp ˚C T2 Sawdust Temp ˚C T3 Asbestos K1 W/mk Saw dust K2 W/mk Watts 2 3 4 . Figure 2. Lagged pipe apparatus . 698w/mk) = 2. The approximate thermal conductivity of lagging material by assuming the heater input to be the heat flow rate through lagged pipe. K1= K2= Thus the thermal conductivity of the given insulating material (Asbestos and Saw dust) has been calculated.RESULT: 1. The heat flow rate through the lagged pipe and compare it with the heater input for known valve of thermal conductivity of lagging material. .15w/mk) = Q When (K2=0. Q When (K1=0.
Report "Thermal Conductivity of Pipe Insulation Using Lagged Pipe"