MECH 1215 LABORATORY THREE (WEEK 16) ADIABATIC COMPRESSION LAB OBJECTIVE 1. On completion of the laboratory the students will have familiarised themselves with polytropic processes, in particular adiabatic and isothermal compressions, and how to experimentally determine the polytropic index from Equation 1. PV = C₁ Thermodynamics lab 2 Where P is the pressure, V is the volume, n is a constant (the polytropic index) that defines the behaviour of the compression process and c, is some constant. 2. STRUCTURE Students will work in groups of 3 or 4, depending on laboratory group size on the day, and each group will carry out up to three (3) repeat experiments for both (1) adiabatic and (2) isothermal compression experiments. However, each student will use the data generated individually. [1] Note 1: You are expected to run each experiments multiple times (a minimum of 3 repeats of each of isothermal and adiabatic compression experiments is required. More is better). Isothermal compression Adiabatic compression (or as close to this as possible) In particular the students will be required to find the value of n for air under conditions of MECH1215: Thermofluids 1 You are expected to find these values within the 2 hour lab session, using a combination of experimentation, mathematical manipulation of equations and data-processing with either excel or MatLab. Once you have found values for n, there is a supplemental question to answer. Details in the sections detailing the tasks to be be undertaken in as part of this lab processes. Laboratory 3 Page 1 of 10 MECH 1215 Introducing ReLOAD Protocol ReLOAD Protocol has been been introduced to the lab this year. This will be used in generation and collation of experimental data. There is also an opportunity for you to use the ReLOAD user interface to evaluate the correctness of your data, particularly you estimated values of polytropic index “n”. Details of the implementation of the ReLOAD protocol is provided in the section on Experiment methodology. 3. DELIVERABLES Thermodynamics lab 2 Each student is required to submit one lab report covering the experiment which should be concise and accurate. Maximum length: 10 pages (excluding cover and reference pages) Important note - Each report should have: Introduction: Putting the work into context and describing the background theory. The introduction should start with some background to the experiment, applications in the real world and relevance of the experiments you are about to undertake. Introduce the appropriate equations and explain the assumptions behind them, their limitations and again relate this to real systems. Aim/Objectives: Explain what your hope to achieve from the lab practical. All aims and objectives should be mentioned. Apparatus A list of the apparatus used and a diagram of the experimental system, with proper labels showing each part/component with a brief description of the function of each (Hand drawing diagrams should be avoided). Methodology: Providing enough information to enable someone to repeat the measurements themselves to the same degree of accuracy. It should have the settings used on any equipment and what controls were in place such as room temperature, placement of equipment, data processing, etc. MECH1215: Thermofluids 1 Laboratory 3 Page 2 of 10 MECH 1215 Results: Conclusions: In a concise form for each task, with the important data clearly highlighted, with no room for interpretation, example calculations provided and all questions within that task answered. Any post- processing of data, curve fitting, figures/plots should be presented and fully described. A description of your data analysis procedure (including any mathematical derivations). Must include graphs and fitted expressions to give n and work for the different scenarios. The results must show repeatability with error bars use to demonstrate this. This will mean that a minimum of two (3) repeats of test is carried out with all measurements recorded. Discussion: Containing an analysis and interpretation of the results based on the information collected and explaining its significance. Identify important issues, discuss the accuracy of the results and explain your findings. Compare your results with theoretical values and standard values from literature (i.e. lecture notes, books, scientific papers). Concise list of the conclusions arising from each experiment. No new information should be contained within this section. References Citations to appropriate literature must be included. Thermodynamics lab 2 Please follow Library referencing guidelines for references and citations: https://library.leeds.ac.uk/info/1402/referencing. The School of Mechanical Engineering follows Leeds Harvard or Leeds Numeric. Select one of these styles and be consistent throughout the report. Formatting exactly as per the guidelines. Please note: Experiments can be done as a group to generate data. The laboratory support staff on ground will guide you on the exact format for this. So please follow their lead. Data processing and report writing MUST be done individually. You are advised to bring your own laptop. This is to allow you start processing your data individually once you have generated your data. You can then be able to ask for further guidance from the support staff around. MECH1215: Thermofluids 1 Laboratory 3 Page 3 of 10 MECH 1215 ● When reporting data, please ensure you use the correct number of decimal places, ensure consistent number of decimal places, and add appropriate labels and units in every plot. All graphs, diagrams and images should be labelled as Figure followed by a number and caption. Do not use Picture 1 for example. Tables should be labelled as Table 1 etc. (It is not necessary to include a graph title when an appropriate figure caption is used and placed underneath the graph). Thermodynamics lab 2 Each section listed in the lab handout must have its own section header and be clearly distinguished from the other sections. Please order the report as per the lab handout. Marks will be awarded for presentation of figures, equations and tables. A Laboratory report should be written in 3rd person, mainly in the present tense. Past tense should only be used when describing the work carried out and the results obtained. Format the document appropriately. Do not provide a report where each task is answered one after another throughout the document. The report should be submitted electronically as per the instructions on Minerva. Standard University penalties will be applied to work handed in after the deadline without mitigating circumstances. MECH1215: Thermofluids 1 Laboratory 3 Page 4 of 10 MECH 1215 Experiment Methodology Adiabatic Gas Law Apparatus You will be provided the apparatus showed bellow. It consists of a piston within a cylinder and mechanical parts to allow a rapid compression, together with the following instrumentation: A pressure probe A temperature probe A position gauge The output signals are fed into a data logger connected to a computer. Arduino software is used to run a suitable programme to acquire the data. ReLOAD is used to provide an interactive platform for running the experiments and collation of generated data. ReLOAD Protocol Thermodynamics lab 2 Note that these task are here to help you work through the laboratory session. The tasks should not form the basis of the structure of the laboratory report i.e. DO NOT write a report which is itemised task 1, task 2 etc. with responses to each individual task. Instead incorporate the work appropriately into the methodology, results and discussion section where suitable. Each of the adaibaitic compression apparatus is assigned a unique number (1 – 8) on ReLOAD. Student MUST check that the number on the compression apparatus to identify the same number on ReLOAD. MECH1215: Thermofluids 1 All students should now have a loggin to ReLOAD from using ReLOAD as part of MECH1010. Laboratory 3 Page 5 of 10