




































Study with the several resources on Docsity
Earn points by helping other students or get them with a premium plan
Prepare for your exams
Study with the several resources on Docsity
Earn points to download
Earn points by helping other students or get them with a premium plan
Community
Ask the community for help and clear up your study doubts
Discover the best universities in your country according to Docsity users
Free resources
Download our free guides on studying techniques, anxiety management strategies, and thesis advice from Docsity tutors
Thermal Engineering Lab Manual
Typology: Study Guides, Projects, Research
1 / 44
This page cannot be seen from the preview
Don't miss anything!
S NO DATE EXPERIMENT PAGE NO MARKS SIGNATURE
1
THERMAL CONDUCTIVITY OF PIPE INSULATION USING LAGGED PIPE APPARATUS
3
2
HEAT TRANSFER THROUGH A VERTICAL PIPE BY NATURAL CONVECTION
8
3
HEAT TRANSFER THROUGH A HORIZONTAL PIPE BY FORCED CONVECTION
15
4
HEAT TRANSFER FROM A PIN FIN APPARATUS (Natural & Forced Convection Modes)
22
5 STEFAN BOLTZMANN CONSTANT 31
6 EMISSITIVITY MEASUREMENT APPARATUS 37
7 PARALLEL FLOW COUNTER FLOW HEAT HEXGHANGER 41
8 PERFORMANCE TEST ON A REFRIGERATION SYSTEM 49
9 PERFIRMANCE TEST ON A AIR-CONDITIONING SYSTEM 55
10
PERFORMANCE TEST ON SINGLE/TWO STAGE RECIPROCATING AIR COMPRESSOR.
61
11 PERFIRMANCE TEST ON A AIR-CONDITIONING SYSTEM
It has a thermal insulation structure placed around a central core of longitudinal axis and it is characterized in that the thermal insulation structure comprises at least one layer consisting of separate solid strips, each strip being wound with a very long pitch and a maximum wind angle to the horizontal axis of less than 30°
Pipe Insulation is thermal insulation used to prevent heat loss and gain from pipes, to save energy and improve effectiveness of thermal systems.
The benefits include, in addition to reducing costs and environmental impacts of energy consumption:
Reducing or eliminating condensation on cold pipes.
Protection from dangerous pipe temperatures. In domestic hot-water systems, the water temperature at the point of use can be closer to the temperature at the water heater, and wait time for hot water can be reduced Control of noise. Reduction of unwanted heat gain to air-conditioned spaces.
PROCEDURE:
Result: Thermal conductivity of lagged pipe is i. K 1 (Asbestos) = _________________w/mº C
ii. K 2 (Saw Dust) = _________________ w/mº
Ex. No: 2 (^) HEAT TRANSFER THROUGH A VERTICAL PIPE BY
Date :^ NATURAL
AIM:
To determine the surface heat transfer coefficient for the vertical tube losing heat by natural convection.
APPARATUS REQUIRED:
= π DL Where D = 0.038 & L= 0.
Thermocouple reading (oC) S.No Time(Min) T1^ T2^ T3^ T4^ T5^ T6^ T7^ T
PROCEDURE:
Forced convection is a mechanism, or type of heat transport in which fluid motion is generated by an external source (like a pump, fan, suction device, etc.). It should be considered as one of the main methods of useful heat transfer as significant amounts of heat energy can be transported very efficiently and this mechanism is found very commonly in everyday life, including central heating, air conditioning, steam turbines and in many other machines. Forced convection is often encountered by engineers designing or analyzing heat exchangers, pipe flow, and flow over a plate at a different temperature than the stream (the case of a shuttle wing during re-entry, for example). However, in any forced convection situation, some amount of natural convection is always present whenever there are g-forces present (i.e., unless the system is in free fall). When the natural convection is not negligible, such flows are typically referred to as mixed convection.
Viva Voice Questions:
AIM: To determine the average surface heat transfer coefficient for a pipe losing heat by forced convection by air flowing through it.Reyonld’s number and nusselt number for each experimental condition to be calculated.
APPARATUS REQUIRED:
1. Forced convection apparatus 2. Stop watch
FORMULAE:
1.
2.
3.
4.
5.
6.
7.
8.
Ex. No: 3 HEAT TRANSFER THROUGH A HORIZONTAL PIPE BY FORCED CONVECTION Date :
RESULT:
i. Surface heat transfer coefficient, ha = _______________ ii. Reynolds number, Re = _______________ iii. Nusslet number Nuthe = _______________ Nuact = _______________
Specifications: Diameter of pin fin, D = 0.012m
Theory: In the study of heat transfer, a fin is a surface that extends from an object to increase the rate of heat transfer to or from the environment by increasing convection. The amount of conduction, convection, or radiation of an object determines the amount of heat it transfers. Increasing the temperature difference between the object and the environment, increasing the convection heat transfer coefficient, or increasing the surface area of the object increases the heat transfer. Sometimes it is not economical or it is not feasible to change the first two options. Adding a fin to an object, however, increases the surface area and can sometimes be an economical solution to heat transfer problems.
Viva Voice Questions:
Forced Convection: 1.
2. m^3 /s
Where, H = difference in levels in manometer
ρw = density of water = 1000 Kg/m^3 ; ρa = density of air at Tmf T 0
3.
4.
5.
6.
TABULATION:
Forced convection:
S.No V(volts) (^) (amps)I^ Fin temperature^
(^0) C Ambient temperature T1 T2 T3 T4 T5^ T
Natural Convection:
S.No V(volts) (^) (amps)I^ Fin temperature^
(^0) C Ambient temperature T1 T2 T3 T4 T5^ T
PROCEDURE :
Procedure:
1. Natural convection: 1. Start heating the fin by switching ON the heater element and adjust the voltage on dimmer stat to say 80 V (increase slowly from zero onwards). 2. Note down the thermocouple readings 1 to 5. 3. When the steady state is reached, record the final reading also records the ambient reading 6. 4. Calculate the heat transfer coefficient and effectiveness of the pin fin using heat transfer relations. 2. Forced convection: 1. Start heating the fin by switching ON heater element and adjust the voltage on dimmer stat equal to 100 V (increase slowly from zero onwards). 2. Start the blower and adjust the difference of level in the manometer with help of gate valve. 3. Note down the thermocouple reading 1 to 5 at the time interval of 5 mins. 4. When the steady state is reached record the final reading 1 to 5 and also record the ambient temperature reading 6. 5. Calculate the heat transfer coefficient and effectiveness of the fin pin using heat transfer relations
Specifications:
Theory:
The Stefan–Boltzmann constant (also Stefan's constant), a physical constant denoted by the Greek letter σ , is the constant of proportionality in the Stefan–Boltzmann law: the total energy radiated per unit surface area of a black body in unit time is proportional to the fourth power of the thermodynamic temperature.
The value of the Stefan–Boltzmann constant is given in SI by
Viva Voice Questions: a. Stefan Boltzmann constant b. State Stefan Boltzmann law? c. What is a black body?
Aim:
To find out the relative viscosity, kinematic viscosity and absolute viscosity of oil sample
by using redwood viscometer and study the variation of viscosity with change in temperature.
Apparatus Required:
1. Stefan Boltzmann apparatus 2. Stop watch
FORMULAE:
Where σ = Stefan Boltzmann constant, ms = Mass of disc in kg dT/dt = Rate of rise in temperature.
Model graph:
Ex. No: 5 STEFAN BOLTZMANN CONSTANT Date :