Reference no: EM132931961

Unit 31 Thermodynamic Principles and Practice - BTEC Level 3 National Extended Diploma in Engineering

Question: Describe the principle of operation of record and reproducer used in the laboratory.

Assignment - Investigate thermodynamic principles and polytropic processes

P1 Explain the fundamental parameters of thermodynamics and their relationship with thermodynamic process parameters

P2 Explain why different temperature scales are used in engineering applications, using examplps to convert between different scales.

P3 Calculate the masses of gases and their final condition parameters for a range of given polytropic processes

M1 Analyse the effects of thermodynamic process parameters on thermodynamic systems, while explaining the need for and correctly converting between different temperature scales.

M2 Calculate accurately the masses of gases, their final condition parameters and the process index 'n' for a range of given polytropic processes

D1 Evaluate the effects of thermodynamic process parameters on thermodynamic systems, while explaining the need for and correctly converting between different temperature scales and calculating accurately unknown values for a range of given polytropic processes

Purpose
Investigate thermodynamic principles related to the expansion and compression of gases that are applied in mechanical systems

Scenario
You are a final year apprentice within an engineering organisation, which specialises in thermal engineering systems. Your supervisor has been observing your progress and is impressed by your knowledge and understanding of the theory which underpins thermodynamic systems. He has asked you to produce a written report which could be used to introduce the subject to future first year apprentices to provide them with a background into the subject.

You are to produce a written report about thermodynamic systems, which:
a) explains the fundamental parameters of thermodynamics and thermodynamic process parameters,
b) explains the need for different types of temperature scale, and
c) evaluates the polytropic processes, explaining the relationships between parameters and what the results from relevant and accurate calculations.
To do this.
Your tutor will provide you with a range of thermodynamic parameters to research and investigate, along with gases to consider when carrying out calculations to an appropriate degree of accuracy and using appropriate units throughout. Your report should contain:
- Explanations of the differences between sensible heat, latent heat, including latent heat of fusion and latent heat of vaporisation and relationship between temperature at constant pressure or volume during expansion and/or compression.
- Calculations of the values and explanations of the significance of the answers:
- Thermal energy of Gas A
- Thermal power of Gas A.
- Explanations for why different temperature scales are needed, and why conversions are carried out between the scales.
You then need to:
- Complete the following calculations, using the data provided for Gases B an C, where Parts 1, 2, 3 and 4 relate to different polytropic processes:

Part 1 - A cylinder of air occupies a volume of 30 litres. The temperature of the gas is T1 and the pressure is P1 (see data table).
Assume the gas constant of air is 287 Jkg-1K-1. Calculate the mass of the air.

Part 2 - A piston contains air at temperature T1 and pressure P1 (see data table). The air is heated to 1200K while being kept at a constant volume of 5 litres.
Assume the gas constant for air is 287 Jkg-1K-1.
Calculate the pressure and the mass of the air following heating.

Part 3 - A cylinder contains a gas at temperature 200°C (T1), volume 5 litres (V1) and a pressure of 2.2MPa (P1). The polytropic process index value (n) of the gas in its initial state is 1.1.
Assume the gas constant for the gas is 188 Jkg-1K-1. Calculate the initial mass of the gas.
The gas is then cooled to a temperature of T2. At this temperature the pressure is P2. Find the polytropic process index value (n) for the gas after it has been cooled.

Part 4 - A gas is stored in a cylinder that has a volume of V1 litres. The gas is stored at temperature T1 and pressure P1. The gas is then released into the air at sea level. Calculate the final temperature of the gas and the polytropic process index value (n) of the gas.
You need to then produce an evaluation of these polytropic processes, explaining the relationships between parameters and what the results of the calculations show in terms of the impact and operation of the thermodynamic system.

Assignment 2: Investigate applications of thermodynamic systems

B.P4 Explain the differences between open and closed loop thermodynamic systems used in given engineering applications
B.P5 Calculate work done, thermal energy transfer and efficiency in given open and closed loop thermodynamic systems
B.M3 Analyse, using the First and Second Laws of thermodynamics, open and closed loop thermodynamic systems in given engineering applications, calculating work done, energy transfer and efficiency accurately
B.D2 Evaluate, using the First and Second Laws of thermodynamics, open and closed loop thermodynamic systems in given engineering applications, calculating work done, energy transfer and efficiency accurately

Scenario:

Your supervisor is pleased with the work that you have done in producing your report that explains the principles of thermodynamics. He would now like you to investigate open and closed loop thermodynamic systems. He would also like you to examine energy transfer within the systems and consider how the laws of thermodynamics are applied to these systems. He would then like you to consider the relationship between thermodynamic principles and parameters and then perform calculations to determine values related to thermal energy for the systems.

You are now to produce a written report which:
a) explores given applications of open- and closed-loop thermodynamic systems,
b) applies the laws of thermodynamics to calculate work done, thermal energy transfer and system efficiencies for given thermodynamic systems, and
c) evaluates the laws of thermodynamics and how these are applied to the given thermodynamic systems.
To do this.
Your tutor will provide you with examples of open-loop and closed-loop thermodynamic systems that you are to research and investigate, along with suitable data that will allow you to carry out calculations to an appropriate degree of accuracy and using appropriate units throughout. Your report should contain:
• research into your given applications of thermodynamic systems and identify the similarities and differences between the open- and closed-loop systems.
• calculations to determine the values of (using the data provided for both a Stirling engine and a heat exchanger):
a. work done in the system
b. output energy from the system
c. energy losses from the system
d. overall system efficiency
e. overall thermal energy transfer.
Using the results of your calculations you then need to produce a balanced evaluation of how the First and Second Law of Thermodynamics are applied to your given open- and closed-loop thermodynamic systems.
You should:
a) consider the interrelationships of the thermodynamic principles and parameters which act on the two systems,
b) consider the advantages and disadvantages of the two different types of system
c) explain the significance of energy losses on the efficiencies of your given systems, referring to your calculations, and
d) provide a suitable conclusion