Department of Mechanical Engineering

MEP341 Thermal Engineering Laboratory (0-0-3)

II Semester 2011-2012

Jan 2, 2012

Guidelines for Laboratory Work

During the preparatory turn, the students are required to spend sufficient time on each rig so as to gain clear understanding of the experimental set-up. Following are the guidelines for the preparatory turn.

Guidelines for Preparation for the Experiments.

The experiments in this course are of two kinds – those involving measurements and those involving only careful study of certain equipment without any measurements.

The guidelines given here are for the first category of experiments.

• Any experiment is first characterized by its OBJECTIVES. Please identify the objectives very clearly.
• To start with, do not look at the experimental rig. Instead try to visualize what kind of experimental set-up would be needed to achieve the given objectives and what measurements would be essential for attaining the objective.
• Only after the above step, should you look at the actual set-up. You must, then, try to understand the actual set-up on your own, identifying all the measurements to be made and try to establish the procedure of the experiment on your own. In the process, you must identify what all information must be provided to you for you to be able to do the experiment. Subsequently, you should verify what you have understood on your own with the instructor. If you carry out all this exercise independently before you start taking measurements, the entire process of experimentation will be much more meaningful to you.
• List the measuring instruments used for various measurements. Think whether these instruments can be replaced by others for measuring the same quantity.
• In any experiment, certain conditions will be more critical than the others. Identify the most critical ones, and not so critical ones for the set-up under study.
• Which quantities do you think need to be measured most accurately in the set-up under study? How should this question be answered?
• Can the same set-up be used for attaining some other objectives pertaining to the phenomena under consideration? What modifications will be required for the purpose?
• Which are the fundamental laws relevant to the phenomena under study? How are they being used for attaining the objectives of the experiment?
• If you were to evaluate someone else doing the experiment, what questions other than those listed above, would you like to ask them?
• Make a list of questions for which answers may not be available readily but have to be searched for.

Guidelines for Doing the Experiment

• You must carry A4 size sheets with objectives and the methodology of the experiment to be carried out already written, graph papers, lab handouts and relevant books for every class.
• You should start recording the measurements only after you have understood the basic principles behind doing the experiment and importance of each measurement. This must be done prior to the lab class hours.
• You must draw a schematic of the set-up used and understand the importance of each component in the set-up.
• All the measurements must be neatly recorded on the final record sheets directly and must be signed by the instructor/TA after the experiment is over. This should be a part of the report of the experiment.
• Every measurement has an uncertainty associated with it. You must carry out an uncertainty analysis in every experiment in which you are making measurements and determine the expected error limits on your experimental results. Hence identify the quantity which should be measured with high accuracy to reduce the overall error substantially.

Guidelines for Report

• Every report must have a cover page with the following information
• Title of the experiment.
• Names and Entry numbers of students who have done that experiment. .
• Group and sub-group.
• Date on which the experiment was done.
• Date on which it was submitted to the instructor/TA for evaluation.

· A template for the above is being provided. Please make copies of this template to be used for each report.

· Please do not reproduce theory from books in your report. The report must give the objectives clearly, a schematic of the experimental set-up with its brief description. The raw data recorded in the laboratory must be a part of the report along with a sample calculation for getting the desired result.

· Only one sample calculation should be done by hand. Repetitive calculations can be performed using a software.

· However, due to lack of printing facility in the lab, the important results will have to be handwritten in the report. The same is also important for you to get the feel for numbers.

· The graphs must be plotted on a graph sheet manually.

· The uncertainty analysis must be included in the report wherever applicable

· The report must include discussion where you give your comments on the results obtained, with possible problems, sources of error, suggestions for improvement etc.

· It is recommended that the group report be prepared jointly so that every member of the group gets to learn each experiment well.

· The report must be prepared in the class itself and submitted at the end of the class. No late submission will be accepted.