VirtLab «Physics. Thermodynamics»

Software laboratory complex for the simulation of laboratory work on the main sections of the course of thermodynamics for technical specialties.

Laboratory equipment is made in accordance with its real analogues. Each laboratory work includes brief guidelines and reference data necessary for the processing of experimental data.

Type of target computing device and supported platform: IBM – compatible PC running Microsoft Windows, Apple Macintosh PC running MacOS, mobile devices based on Android and iOS operating systems. Additionally, program execution is possible in a web browser environment with support for HTML5 technology and hardware support for 3D graphics (WebGL technology).

Graphics software uses OpenGL 2.0 components. The graphical user interface of the program is implemented in English and Russian.

Multi-platform support allows you to use the software on various computing devices, including interactive whiteboards, smartphones, tablet and desktop computers, which, in turn, increases the flexibility and mobility of the educational process, corresponding to the modern level of education informatization. The web version allows the integration of software into distance e-learning systems.

Laboratory complex includes laboratory works:

1. Increase of Internal Energy by Mechanical Work
Theme: Internal Energy

OBJECTIVE: Verifying the First Law of Thermodynamics.

SUMMARY: The experiment is to investigate the increase of internal energy of an metal body caused by friction. The increase can be observed by measuring the increase in the temperature of the body, which is proportional to the work done, as the body undergoes no change in the state of aggregation and no chemical reaction occurs. To eliminate the effect of heat exchange between the metal body and the environment as far as possible, begin the series of measurements slightly below room temperature and end the series at a temperature slightly above room temperature. The difference below and above room temperature prior to starting the measurements and at the point of concluding them should approximately be the same.

2. Internal Energy and Electrical Work
Theme: Internal Energy

OBJECTIVE: Increasement internal energy of body by means of electrical work.

SUMMARY: This experiment investigates how the internal energy of cuprum and aluminium calorimeters can be increased by electrical work. As long as the aggregate state does not change and no chemical reactions occur, it is possible to determine the increase in internal energy from the rise in temperature to which it is proportional. In order to prevent heat being transferred from the calorimeters to their surroundings, the series of measurements should start at a temperature somewhat below the ambient temperature and finish at a temperature only slightly above that of the surroundings.

3. Boyle's Law
Theme: Gas Laws

OBJECTIVE: Measurement at room temperature in air as an ideal gas.

SUMMARY: The experiment verifies Boyle’s Law for ideal gases at room temperature, taking air as an ideal gas in this experiment. The volume of a cylindrical vessel is varied by the movement of a piston, while simultaneously measuring the pressure of the enclosed air.

4. Amontons' Law
Theme: Gas Laws

OBJECTIVE: Verifying the linear relationship between the pressure and temperature of an ideal gas.

SUMMARY: The validity of Amontons’ law for ideal gases is demonstrated using normal air. To demonstrate this, a volume of enclosed air located in a hollow metallic sphere is heated with the aid of a water bath while the temperature and pressure are being measured at the same time.

5. Adiabatic Index of Air
Theme: Gas Laws

OBJECTIVE: Determination the adiabatic index Cp/Cv for air using Rüchardt’s method.

SUMMARY: In this experiment an aluminium piston inside a precision-manufactured glass tube extending vertically from on top of a glass vessel undergoes simple harmonic motion on top of the cushion formed by the volume of air trapped inside the tube. From the period of oscillation of the piston, it is possible to calculate the adiabatic index of air.

6. Real Gases and Critical Point
Theme: Gas Laws

OBJECTIVE: Quantitative analysis of a real gas and determining its critical point.

SUMMARY: The critical point of a real gas is characterised by the critical temperature, the critical pressure, and the critical density. Below the critical temperature, the substance is gaseous at large volumes and liquid at small volumes. At intermediate volumes it can exist as a liquidgas mixture, in which changing the volume under isothermal conditions causes a change of state: the gaseous fraction increases as the volume is increased, while the pressure of the mixture remains constant. As the liquid and the vapour have different densities, they are separated by the gravitational field. As the temperature rises, the density of the liquid decreases and that of the gas increases until the two densities converge at the value of the critical density. Above the critical temperature, the gas can no longer be liquefied. However, under isothermal conditions the gas does not obey Boyle’s Law until the temperature is raised considerably above the critical temperature.

7. Leslie Cube
Theme: Heat Transfer

OBJECTIVE: Measure the heat radiated by a Leslie cube.

SUMMARY: The radiation emitted by a body depends on its temperature and the nature of its surface. More specifically, according to Kirchhoff’s law, the ratio between emissivity and absorptivity is identical for all bodies at a given temperature and corresponds to emissivity of a black body at this temperature. In this experiment, we will heat the water-filled Leslie cube to a temperature of 100°C and ascertain the radiated intensity in a relative measurement using a Moll thermopile.

8. Heat Conduction
Theme: Heat Transfer

OBJECTIVE: Measure conduction of heat in metal bars.

SUMMARY: Conduction of heat involves heat being transferred from a hotter part of an object to a colder area by means of the interaction between neighbouring atoms or molecules, although the atoms themselves remain in place. In a cylindrical metal bar with ends maintained at different temperatures, a temperature gradient will emerge along the bar after a while. The temperature decreases uniformly from the warm end to the cold end and a constant flow of heat arises through the bar. The way the situation changes from a dynamic state to a steady state is observed by means of repeated measurements to determine the temperatures at various measurement points. The metal bars are electrically heated so that the flow of heat in the steady state can be determined from the electrical power supplied.

9. Thermal Expansion of Solid Bodies
Theme: Thermal Expansion

OBJECTIVE: Determine the coefficients of expansion for brass, steel and glass.

SUMMARY: If solid bodies are heated up, they generally expand to a greater or lesser degree. In this experiment, hot water is allowed to flow through tubes made of brass, steel and glass. The expansion in their length is measured using a dial gauge. The linear expansion coefficients for the three materials are then calculated from the change in their length.

10. Water Anomaly
Theme: Thermal Expansion

OBJECTIVE: Determine the temperature where water reaches its maximum density.

SUMMARY: Water is unlike most other materials in that up to a temperature of about 4°C it initially contracts and only starts expanding at higher temperatures. Since the density is inversely related to the volume of a mass, water thus reaches its maximum density at about 4°C.

11. Stirling Engine D
Theme: Thermodynamic Cycles

OBJECTIVE: Operating a functional model of a Stirling engine as a heat engine.

SUMMARY: A hot-air engine is a classical example of a heat engine. In the course of a thermodynamic cycle thermal energy is fed in from a high temperature reservoir and then partially converted into useable mechanical energy. The remaining thermal energy is then transferred to a reservoir at a lower temperature.

12. Stirling Engine G
Theme: Thermodynamic Cycles

OBJECTIVE: Demonstration of the operation of the gamma-type Stirling engine as a heat engine, heat pump and refrigerator.

SUMMARY: Cyclic processes in thermodynamics can be plotted as a closed loop in a p-V diagram. The area enclosed by the curve corresponds to the mechanical work taken from the system. Alternatively, the mechanical power associated with a complete cycle can be determined and then the mechanical work can be calculated from that by means of an integration over time. This will be investigated in the course of an experiment using a gamma-type Stirling engine.

13. Heat Pumps
Theme: Thermodynamic Cycles

OBJECTIVE: Record and analyse the pressure-enthalpy diagram for a compression heat pump.

SUMMARY: An electric compression heat pump consists of a compressor with a drive motor, a condenser, an expansion valve and an evaporator. Its functioning is based on a cyclical process with phase transition, through which the working medium in the pump passes; ideally, this process can be divided into the four steps comprising compression, liquefaction, depressurisation and evaporation. The theoretical performance coefficient of an ideal cyclical process can be calculated from the specific enthalpies h1, h2 and h3 read from a Mollier diagram. Determining the enthalpies h2 and h3 of an ideal cyclical process and the quantity of heat supplied to the hot water reservoir per time interval Δt makes it possible to estimate the mass flow of the working medium.

Main links:
System Requirements

- CPU: Intel/AMD, at least 2 GHz;
- RAM: at least 1 GB;
- VRAM: at least 512 MB;
- Screen Resolution: at least 1024x768x32;
- OpenGL version 2.0.
- DirectX version 9.0.c (for Windows OS);
- Standard keyboard and computer mouse with scroll wheel;
- Means of playing sound (audio speakers or headphones).

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