Stirling motors¶

Prerequisite¶

Whom it is addressed to

This laboratory activity is intended for physics students who have already received basic knowledge of thermodynamics with particular reference to the operating principles of thermal machines. No programming knowledge or knowledge of the python language is necessary.

Connected lesson: : Basic-python_commands.

Time constraints:

• starting from 90 min - double lesson (additionally 90 min for Basic-python_commands.)

Preparing For This Tutorial:¶

The materials used for this laboratory are listed below. They were mounted as shown in the figure 1.

• A Stirling cycle thermal machine

• A temperature sensor

• A brightness sensor

• The programmable logic unit MINDSTORM EV3

• A kettle for the production of water vapor

• A second thermometer to check the temperature of water vapor

The Stirling machine is positioned above the heat source, and the sensors connected to the MINDSTORM EV3 logic unit are positioned on it.

Figure 1.: the experimental apparatus

Effects¶

Educational objectives

The purpose of this workshop is multiple and consists in providing students with knowledge on various levels listed below:

1. a qualitative knowledge of the operating principles of a thermal machine.

2. a qualitative knowledge of what a programmable logic unit is and how it can be used

3. The basic knowledge to perform a quantitative measurement of frequency and temperature using a programmable logic unit

4. The basic knowledge to implement a program in the Python language

5. The basic skills for the creation of algorithms to be implemented in a programming language.

Exercise¶

Analysis of the energy efficiency of a thermal machine.

Example solution¶

1. Project presentation

In this first phase the teacher recalls the knowledge of thermodynamics related to thermal machines and their performance. The realization of this point is scheduled on a two-hour lesson.

2. Creating an algorithm

A two-hour lesson will be needed to create with the students an algorithm that will achieve the purpose of this laboratory.

3. Coding for beginners

In this second phase the teacher will provide students with a copy of the Basic-python_commands. Students will follow the instructions on the form, acquiring the basic knowledge for the creation of codes. The realization of this point is scheduled on two-hour lessons.

4. Specific programming of the EV3-Mindstorm unit

In this fourth phase the teacher will provide students with a copy of the Stirling_Laboratory_01. Students will follow the instructions on the card, acquiring basic knowledge for using EV3-Mindstorm sensors in a program written in the Python language. The realization of this point is scheduled on a two-hour lesson.

5. Realization of data acquisition software

In this fifth sentence the two software used for the realization of this laboratory must be analyzed. The teacher shows the students the software and with them he analyzes the implemented algorithm. The purpose of this module is to make students aware of the software structure, they do not necessarily need to be able to implement it independently, but must be able to read it and understand the algorithm. The realization of this point is scheduled on two two-hour lessons.

6. Data taking

In this sixth and last phase the experimental apparatus is assembled and the measurement is carried out. The realization of this point is scheduled on a two-hour lesson.