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    Conduction Manual

    Uploaded by

    Ashish Meena
    The document provides instructions for conducting experiments on heat conduction using a thermal science laboratory unit. It describes the equipment used to study linear and radial heat conduction. The linear conduction unit consists of a heater, inserts of different materials and diameters, and a cooler. The radial conduction unit contains a disc with a central heater and outer cooling ring. Students are instructed to install inserts, supply power to the heater, record steady-state temperatures at measurement points, and calculate the thermal conductivity. Guidelines are provided for documenting the procedure, presenting results in tables and graphs, and analyzing errors.

    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd

    Conduction Manual

    Uploaded by

    Ashish Meena
    18 views7 pages
    The document provides instructions for conducting experiments on heat conduction using a thermal science laboratory unit. It describes the equipment used to study linear and radial heat conduction. The linear conduction unit consists of a heater, inserts of different materials and diameters, and a cooler. The radial conduction unit contains a disc with a central heater and outer cooling ring. Students are instructed to install inserts, supply power to the heater, record steady-state temperatures at measurement points, and calculate the thermal conductivity. Guidelines are provided for documenting the procedure, presenting results in tables and graphs, and analyzing errors.

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    conduction lab manual

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    The document provides instructions for conducting experiments on heat conduction using a thermal science laboratory unit. It describes the equipment used to study linear and radial heat conduction. The linear conduction unit consists of a heater, inserts of different materials and diameters, and a cooler. The radial conduction unit contains a disc with a central heater and outer cooling ring. Students are instructed to install inserts, supply power to the heater, record steady-state temperatures at measurement points, and calculate the thermal conductivity. Guidelines are provided for documenting the procedure, presenting results in tables and graphs, and analyzing errors.

    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd
    Download as pdf or txt
    18 views7 pages

    Conduction Manual

    Uploaded by

    Ashish Meena
    The document provides instructions for conducting experiments on heat conduction using a thermal science laboratory unit. It describes the equipment used to study linear and radial heat conduction. The linear conduction unit consists of a heater, inserts of different materials and diameters, and a cooler. The radial conduction unit contains a disc with a central heater and outer cooling ring. Students are instructed to install inserts, supply power to the heater, record steady-state temperatures at measurement points, and calculate the thermal conductivity. Guidelines are provided for documenting the procedure, presenting results in tables and graphs, and analyzing errors.

    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd
    Download as pdf or txt
    of 7

    INSTRUCTION MANUAL

    FOR
    THERMAL SCIENCE LABORATORY EXPERIMENTS

    HEAT CONDUCTION

    INDIAN INSTITUTE OF TECHNOLOGY GUWAHATI


    DEPARTMENT OF MECHANICAL ENGINEERING
    NORTH GUWAHATI, GUWAHATI-781039
    2
    GENERAL INSTRUCTIONS

    1. The instructions in this manual provide only the outline. Come prepared with the back-up
    material i.e. go through the theory related to the experiments, know in advance the
    readings to be taken, the calculations to be performed and the results to be presented

    2. The data sheets are to be countersigned by the instructor. The calculations are to be
    completed and checked by the instructor on the same day. The complete report should be
    submitted on the day of next lab class.

    3. Each student has to submit his/her individual report and his/her individual comments and
    remarks.

    4 The report should include


     The aim of the experiment
     A sketch/block diagram of the apparatus
     A listing of the instruments used with details (type, range, accuracy etc.)
     Transient/steady state readings in tabular form
     Results in graphical form where required
     Comments and natures of the results with standard/reference values.
     Source of errors and error analysis.

    5. The report need not include


     A description of the Apparatus
     A description of the experimental procedure

    6 The following points should be attended before starting the experiment.


     Take note of any precaution with regard to the experimental set-up
     Check electrical connections before starting the experiment.
     Clarify any doubt with regard to the experiment
     Do not put on the computer attached to the set-up

    DO NOT PUT ON THE SYSTEM UNTIL THE CONNECTION ARE CHECKED BY THE
    INSTRUCTOR
    3

    HEAT CONDUCTION
    LINEAR CONDUCTION
    dT
    Heat conduction through a wall is given by Q̇ = -k A .The conduction through a wall made
    dx
    up of several layers is given by
    Where Q̇= Heat Flow rate
    k= Thermal Conductivity
    A= Cross sectional area perpendicular to the
    heat flow direction.
    dT= Change in temperature

    k1 k2 k3

    T1

    T2
    T3

    T4

    l1 l2 l3

    First Layer: Q̇=k1 A (T1-T2)/l1


    Second Layer: Q̇=k2 A (T2-T3)/l2
    Third Layer: Q̇=k3A(T3-T4)/l3

    A(T1-T4)
    ̇Q = ----------------
    l1/k1+l2/k2+l3/k3

    RADIAL CONDUCTION
    It corresponds to the conduction of the heat through a hollow cylinder and is given by
    2 L k (T1-T2)
    ̇Q= ---------------------
    ln(r2/r1)
    ̇
    Where Q= Rate of Heat flow
    L= Thickness of disc
    T1, T2 temperature at r1 and r2
    4
    DESCRIPTION: The linear conduction unit comprises of three elements namely the heater,
    various inserts and a movable part with a cooler. By opening the toggle fastener and sliding back
    the cooler, the insert can be installed. By this means the heat is transferred linearly from the
    heater through an insert to the cooler. The heater consists of external insulation, lid, brass rod
    and the electrical heater element. There are three measuring points under the insulation in the
    brass rob. Together, with the insert, there are nine measuring points. Three different types of
    insert rods can be inserted in order to measure the linear conduction. Insert 1 has three
    temperature measuring points in a brass rod. This brass rod has the same diameter as the heater
    and the cooler. Insert 2 also has the same diameter as the heater and the cooler, but is made from
    corrosion resistant steel and does not have temperature-measuring points. Insert 3 is made of
    brass but of lesser diameter 15mm and it also does not have measuring points. The cooler
    consists of external insulation and a brass rod as for the heater. However, this brass rod has bores
    through which the cooling water can flow. The distance between adjacent measuring points is 10
    mm. The diameter of the heater, cooler, insert 1and insert 2 is 25 mm. If insert 1 is not used in
    the experiments, the temperature displayed measuring 4,5, and 6 should be ignored.

    The radial conduction unit consists of an insulating housing with lid and disc with heater and
    cooler. The heater is fixed from below in the center of the brass disc. There is copper pipe around
    the disc through cooling water can flow. From above, six temperature-measuring points are fitted
    in a line that stretches radially from the center to the circumference. In radial conduction, the
    measuring points are numbered from the center to outwards. The distance between adjacent
    measuring points is 10 mm. The diameter of the disc is 110 mm; it is 4 mm thick. The heater is
    in the center of the disk on the underside and has a diameter of 12 mm. The temperatures for
    measuring points 7, 8 and 9 should be ignored during the experiments.

    The control and display unit has a digital temperature (deg C) and power (Watts) display. The
    measuring point for the temperature display is selected by a rotary knob. The heater power is
    switched with on\off switch and adjusted using potentiometer. The measuring points in linear
    and radial conduction are shown in Fig1 and Fig2.

    PROCEDURE:
    1. Install the insert 1 adjust the cooling water flow rate (only a very low cooling water flow rate
    of approximately 1 liter/hour is required to dissipate a heater power of 90 W at a temperature
    difference of 900 C).
    2. Switch on the unit and adjust the power to 40 W using the potentiometer of the control and
    display unit.
    3. When the thermal conduction process has reached a steady state condition, i.e., the
    temperatures at the individual measuring points are stable and no longer changing, note the
    temperatures at various locations and the power supplied to the heater.
    4. The same procedure holds good for all the inserts and for both the linear and radial
    conduction.
    5
    WARNING:

    1. Do not operate the conduction unit above 1200 C. The plastic part disintegrates after this
    temperature.
    2. Never operate the conduction unit without cooling water. The unit gets overheated.
    3. Do not connect the heater directly to mains.
    4. Always switch off the control and display unit prior to changing the power supply.
    Otherwise, the temperature sensors may get damaged.

    RESULTS:
    Plot a graph with temperature vs. location of the thermocouple. At each location of the
    thermocouple, calculate the thermal conductivity.

    Figure 1: Measuring points for linear Conduction

    Figure 2: Measuring points for radial Conduction


    6
    Data Sheet for linear conduction:

    Insert-1. Material:_____________Length: Diameter: .

    Heat T1 T2 T3 T4 T5 T6 T7 T8
    Sl. Input
    No Q
    1

    Insert-2. Material:_________________Length: Diameter: .

    Heat T1 T2 T3 T4 T5 T6 T7 T8
    Sl. Input
    No Q
    1

    Insert-3. Material:_________________Length: Diameter: .

    Heat T1 T2 T3 T4 T5 T6 T7 T8
    Sl. Input
    No Q
    1

    3
    7

    Data Sheet for Radial conduction:

    Material:________________Thickness: Diameter: .

    Sl no Heat Input T1 T2 T3 T4 T5 T6

    01

    02

    03

    Guidelines for Report Preparation

    1. Sample calculation
    2. Uncertainty analysis (Uncertainty in temperature: ±(0.1-0.2)°C; Uncertainty in
    dimension:± (0.02-0.04)mm; Uncertainty in power: ± 1 W)
    3. Result and plotting of temperature distribution profile on graph paper
    4. Discussion
    5. Source of error

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