1. Thermal Conductivity by Guarded Hot Plate Method.
The ‘J.P.T.I.’ unit consists of a guarded hot plate assembly formed by a central heater and sandwitched between the lower and upper plates and rings. Two identical specimen of the material to be tested are clamped between the two cooling plates and the heater plate assembly. Heater input to central heater measured by voltmeter and ammeter giving the heat flow rate across the specimen. Thermocouple are placed in heater and cooling plated to measure the temperature difference across the specimen.
2. Thermal Conductivity of Insulating Powder.
The ‘J.P.T.I.’ unit consists of two thin wall concentric copper spheres. The inner sphere house the heating coil. Heating coil is made up of nichrome wire wound on mica sheet. The insulating powder packed between two shells. Power supply to the heater is given through a dimmerstat & is measured by voltmeter & an ammeter.Temperature can be measured with the help of thermocouples. Four thermocouple are embedded on inner sphere and six thermocouples are embedded on outer sphere .
3. Thermal Conductivity of Metal Rod.
The ‘J. P. T. I.’ unit consists of a copper bar, which is heated at one end ,a heat sink is provided at other end. The test section of bar is properly insulated and along the length of bar, thermocouples are attached. Heat conducted through the section of bar is mea sured by heat collection in water cooled heat sink. A panel comprising of controls and measurements is provided, which provides easy operation and study mounting of unit. Bar of different metal other then copper can be provided, on request at extra cost.
4. Shell & Tube Heat Exchanger ( Water to Water Type )
The ‘JPTI’ unit consists of a two pass design in which a mild steel shell houses the copper tubes. The baffle in the end box make the tube arrangement at the center to make the heat exchanger of two-pass type. The cold fluid, i.e. cold water enters the shell & flows over the tubes. Hot fluid is hot water, which is obtained from a geyser .Temperature of hot water & cold fluids measured by thermometers. By measuring the flow rates & temperatures of hot & cold fluids, performance of heat exchanger viz. LMTD heat transfer rate & heat transfer coefficient can be determined.
5. Parallel Flow / Counter Flow Apparatus.
The ‘J. P. T. I.’ unit consists of a tube in tube type concentric tube type exchanger hot fluid flow through inner tube and cooling water flows through the annulus. The appara tus is mounted on a board with system of valves and pipes. Hot fluid flows always in one direction & cold fluid flow direction can be changed accordingly. Inlet temperature of heat exchanger can be measured by thermometers. A electric geyser is used to heat the water. Outer tube of the heat exchanger is provided with adequate insulation to minimise the heat losses.
6. Critical Heat Flux Apparatus.
The ‘J P T I’ unit consists of a cylindrical glass container containing distilled water. Heating surface is in the form of a Nichrome heating wire completely surbmerged in the water. Thermometer is provided to measure the temperature of water in the container, variac is provided to supply electrical input to the test heating wire.
7. Stefan Boltzmann Apparatus.
The ‘J. P. T. I.’ unit consists of a hemisphere surrounded by hot water. The instrument determines stefan boltzmann constant. Water heating tank is provided to supply hot water. Stefan Boltzmann constant is determined from the temperature raise rate when blackned disc is inserted at the center of disc from hemisphere by radiation & its temperature begins to rise.
8. Emissivity Measurement Apparatus.
The ‘JPTI’ unit consists of a two circular aluminium plates of identical dimensions. One of the two plates is the blackened and considered as black surface. While other plates is the test plates. Both the plates have Nichrome wire heater bound in mica sheet attached to them. Both the plates are keep in close enclosure. Supply of heat to both the plates is given by different variacs measured by a voltmeter & ammeter. Heat input to both the plates can be read with the help of SPDT switches. A temperature indicator is provided to measure the temperature of both the plates.
9. Forced Convection Apparatus.
The ‘JPTI’ unit consists of mainly a centrifugal blower, electrically heated test sec tion, control valve to regulate the air flow and an orificemeter and U-tube water manom eter for flow measurement. Thermocouples are used to measure the pipe wall tempera ture and also the air temperature at inlet and exit. The apparatus mainly designed to find out the value of heat transfer coefficient under the air different conditions.
10. Natural Convection Apparatus.
The ‘J P T I’ unit consists of vertical cylinder fitted in a large enclose, with top and bottom open to ensure undisturbed natural convection apparatus. Perspex sheet provided at the front side of enclosure for visual display. Heating element provided inside the cylinder to heat it uniformly and the heat is dissipated from other surface by natural convection to ambient air. Thermocouples cylinder surface and one more thermo couple records the ambient temperature in the duct. The heater input can be varied with the help of a dimmerstat and measured by voltmeter and an ammeter.
11. Pin Fin Apparatus.
The ‘J.P.T.I.’ unit consist of a brass or aluminium fin of a circular cross section fitted across at one end of a long rectangular dust.
The other end of the duct is connected to suction side of the blower and the air flows past the fin perpendicular to it’s axis. One end of the fin projects outside the duct & is heated by an electric heater. Temperature at five points along the length of the fin are measured by thermocouples. The blower is not run in natural convection condition while it is run in forced convection conditions. The air flow rate can be varied by control valve on delivery side of the blower.
12. Heat Pipe Apparatus.
The ‘J.P.T I’ unit consists of 3 identical cylindrical conductors in respect of geometry. One end of these is heated electrically while there are small capacity tanks acting as heat sinks at the other end. The unit consist of a heat pipe, a copper pipe & stainless steel pipe.
Thermocouples are embedded along the lengths to measure the temperature distribu tion & the heat transfer rate is noted in terms of the temperature rise in the heat sink tanks.
Performance of heat pipes as a super conducting device could be studied well in terms of the temperature distribution along the length at a given instant and could be com pared with other two members.
The apparatus could be operated under different heat input rates to the heaters.
13. Lagged Pipe Apparatus.
The ‘J.P.T.I’ unit consist of a three concentric pipes of a very small thickness as com pared to diameter. They are arranged concentrically over two supports and closed with the help of two disces. The annual in between the cylinders are filled completely by two different insulating materials. Thermocouples at proper position are used to mea sure the temperature. Inside the inner pipe a nicrome wire heater is placed. Heat input to the heater is given through a variac and measured by a voltmeter and ammeter. By varying the heat input rates wide range of experiments can be performed.
14. Composite Wall Apparatus.
The ‘J.P.T. I.’ unit consist of a three slabs of different materials namely mild steel, wood & backlite. Nicrome heater is provided to supply heat input across these com posite walls. Total heater assembly comprises of a heater bound between two alu minium plates, on both sides of this heater identical structures of composite wall are placed. Thermocouples are provided at proper position in the composite wall to record desired inside temperature of composite wall. Multichannel temperature indicator is used to measure these temperature. Small hand press provided to press the wall on each other & to ensure that no air gap remaining between two plates. Heat input to heater is given through a variac & measured by voltameter & ammeter. By varing heat input & combinations of the composite structure wide range of experiment can be performed.
15.Thermal Conductivity of Liquid.
The ‘J.P.T.I.’ unit consists of a apparatus is based on guarded hot plate method & cold plate method. A thin horizontal layer of liquid, under test is sandwitched between hot and cold plate. Hot and guard plates are heated by specially
designed electrical heaters. Hot & cold plates are circular in shape and are made from good conducting materials. A circular trough is formed on cold plate to hold the liquid during testing. A coolant water will circulate through cold plate continuously. Cr-Al thermocouples are used for temperature measurement.
16. Condensation in Drop & film Apparatus.
The ‘JPTI’ unit consist of a transparent gas cylinder at the top of which two cylinders hang & steam is also admitted at the top one of the condenser is provided with chrome plated surface and other with natural surface finish to promote film wise condensation water is circulated through the condensers from common intel. The transparent cylinder allows visualisation of condensation process. A rotameter measure the water flow & a pressure gauge show the steam pressure. A digital temperature indicator mea sures temperatures at various points.
17. Unsteady State of Heat Transfer Apparatus.
The ‘JPTI’ unit consist of small test cylinder. The cylinder is heated by a hot bath, till steady state is reached and then cooled in air . During both, heating & cooling, temperature of the cylinder is function of time & hence heating & cooling of cylinder are unsteady state heat transfer process. The temperature of test cylinder is measured with the help of thermocouple. The hot bath is pro vided with heater with input control for experimentation of different bath tem peratures.
