ME495 Lab 01_ Brayton Cycle

pdf

School

San Diego State University *

*We aren’t endorsed by this school

Course

495

Subject

Mechanical Engineering

Date

Apr 3, 2024

Type

pdf

Pages

Uploaded by ChiefDeerMaster1083

Brayton Cycle ME 495: Mechanical and Thermal Systems Lab Section 05: Thursday Group D Authors: Soeung Khanitha, Smith Emilee, Sichantha Jack, Taylor Charles Instructor: Dr. Hamid Nourollahi Experiment Performed, Date: Thursday, March 14th, 2024 Report Due, Date: Thursday, March 21, 2024

1 Table of Contents Objective of Experiment (Khanitha Soeung) ................................................................................................. 2 Equations and Symbols (Emilee Smith) .................................................................................... 3 Equipment (Khanitha Soeung) ....................................................................................................................... 3 Experimental Setup (Khanitha Soeung, Jack Sichantha) ............................................................................... 5 Experimental Procedure (Khanitha Soeung & Jack Sichantha) ..................................................................... 5 Experimental Results (Jack Sichantha & Emilee Smith & Charles Taylor) .................................................. 6 Discussion of Results (Charles Taylor) ........................................................................................................ 14 Conclusion (Charles Taylor ) ....................................................................................................................... 14 References ( Khanitha Soeung ) ................................................................................................................... 15 Appendix ...................................................................................................................................................... 15 List of Figures Brayton Cycle .......................................................................................................................... 0 Figure 1: Axial flow gas turbine manufactured by Armfield Tech. Ltds ................................................ 5 Figure 2: Actual Brayton P-V for Sample 1 .............................................................................. 7 Figure 3: Actual Brayton T-S for Sample 1 .............................................................................. 7 Figure 5: Actual Brayton T-S for Sample 2 .............................................................................. 8 Figure 7: Actual Brayton T-S for Sample 3 .............................................................................. 9 Figure 9: Actual Brayton T-S for Sample 4 ............................................................................ 10 Figure 11: Actual Brayton T-S for Sample 5 ........................................................................... 11 Figure 12: Ideal Brayton T-S .................................................................................................. 12 Figure 13: Ideal Brayton P-V ................................................................................................. 12 List of Tables Table 1: Equations ............................................................................................................................. 3 Table 2: Thermal Efficiency of Brayton Cycle for Each Engine Speed ......................................... 12 Table 3: First law analysis of each section at each engine speed ................................... 13 Table 4: Back Work Ratio for each engine speed ............................................................ 13

2 Objective of Experiment (Khanitha Soeung) The objective of this laboratory exercise is to acquire hands-on experience with the Brayton cycle, a thermodynamic cycle that describes the operation of gas turbines, by using empirical data from a Model CM14 Axial Flow gas turbine as well as referencing Lab 01 procedure and guides provide by Dr.Nourollahi The Brayton cycle is comprised of four main processes: compression, combustion, expansion, and exhaust. During the compression process, air is compressed by the compressor section of the gas turbine. The compressed air then enters the combustion chamber where fuel is added and combustion occurs, leading to a significant increase in temperature and pressure. Subsequently, the high-pressure, high-temperature gas expands through the turbine section, producing thrust or shaft work. Finally, the exhaust gasses are expelled from the system. The cold-air-standard assumption is often used in the analysis of gas turbine cycles, assuming that the air behaves as an ideal gas with constant specific heats throughout the cycle and neglecting any heat transfer with the surroundings. The team aims to validate the theoretical Brayton cycle model against empirical measurements obtained from the gas turbine, thereby affirming the cycle's applicability in practical gas turbine systems. By comparing the theoretical predictions with actual experimental data, the team can assess the accuracy of the Brayton cycle model and gain insights into the performance characteristics of the gas turbine under various operating conditions. This validation process contributes to a deeper understanding of gas turbine operation and enhances the ability to design, optimize, and analyze such systems for various applications, including aircraft and ship propulsion and power generation. The team hypothesizes that the errors will be primarily systematic during this process because the data is driven primarily by machine instead of human. The team also hypothesizes that data will be most efficient in the section of no pressure change, e.i. between points 2,3 and 1,4.

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version

Access to all documents
Unlimited textbook solutions
24/7 expert homework help

3 Equations and Symbols (Emilee Smith) Table 1: Equations Equation 1: Thermal Efficiency η ?ℎ,???𝑦??? = 1 − 1 ? ? (𝑘−1)/𝑘 Equation 2: Pressure Ratio ? ? = ? 2 /? 1 Equation 3: Specific Heat Ratio 𝑘 = 1. 4 Equation 4: Back work ratio ? ?𝑤 = 𝑤 ??𝑀?,𝑖? 𝑊 ??𝑅?,??? Equation 5: First Law for Compressor − 𝑤 ? = ? ?,? (? ?,??? − ? ?,𝑖? ) Equation 6: Efficiency of the Compressor η ? = ? ???,? −? 𝑖? ? ???,? −? 𝑖? Equation 7 ? ? = ? ?,? (? ?,??? − ? ?,𝑖? ) Equation 8: First Law for Turbine − 𝑤 ? = ? ?,? (? ?,??? − ? ?,𝑖? ) Equation 9: Efficiency of Turbine η ? = ? ???,? −? 𝑖? ? ???,? −? 𝑖? Equipment (Khanitha Soeung) ● Model CM14 Axial Flow Gas Turbine ○ Main component of the experiment, representing a simple gas turbine engine to study the Brayton cycle. ● Transparent Polycarbonate Safety Screen ○ Provides protection by enclosing the engine and preventing contact with moving parts.

4 ● Fuel Tank with Aeroshell 500 Turbine Oil Mixture ○ Supplies fuel to the engine for combustion during operation. ● Electronic Console ○ Controls the engine operation and facilitates data acquisition for analysis. ● PC with Armfield Software ○ Monitors engine performance, collects data, and aids in analysis of experimental results. ● Sensors ○ Measure various parameters such as temperature, pressure, shaft speed, and thrust to provide data for analysis. ● Ear Protection Gear ○ Ensures safety by reducing exposure to loud engine noise during operation. ● Power Outlet and Cord ○ Supplies electrical power to the Electronic Console for operation. ● Data Recording Tools (Manual Sampling Button, Integrated Spreadsheet) ○ Facilitate data collection during engine operation for analysis.

5 Experimental Setup (Khanitha Soeung) Figure 1: Axial flow gas turbine manufactured by Armfield Tech. Ltds. Experimental Procedure (Khanitha Soeung & Jack Sichantha) This procedure is entirely in reference to the lab guide manual in combination with the team’s experience during the lab experiment. This manual is referenced in the references section of this report as reference [1]. In the laboratory experiment, the Professor and TA guided the team through the inspection procedure. They inspected the compressor/turbine for free rotation and ensured no obstructions were present in front of the CM-14 engine's intake or exhaust. Fuel and oil levels were checked, and the transparent polycarbonate safety screen was securely fitted and clamped. Any spilled fuel around the plinth was also checked and cleared. The red button on the Electronic Console was kept off, and the console was connected to a power outlet using the supplied cord, with a USB cable connected to the PC. The full fuel tank was positioned appropriately, and the Armfield software was activated on the PC, displaying useful

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version

Access to all documents
Unlimited textbook solutions
24/7 expert homework help

6 engine readings. Before starting the engine, the "zero buttons" were clicked on all sensor edit fields to compensate for any residual sensor errors. Following the correct sequence, the engine was started by clicking the 'Power On', 'Enable', and 'Start' buttons on the PC screen. The startup sequence was initiated, and upon clicking the 'Start' button, the electric starter attempted to start the engine after a delay. Samples were taken using the manual sampling button in the Armfield software, and subsequent runs were conducted as per the professor's instructions. Specific graphs were displayed using the 'View Graph' button, and after data collection, the engine was powered down using the appropriate controls. Results were collected and recorded in the 'Table' section of the Armfield software for analysis. Experimental Results (Jack Sichantha & Emilee Smith & Charles Taylor) 1. Provide a T – s diagram and a P – v diagram for the ideal and actual Brayton cycle for each test speed.

7 Figure 2: Actual Brayton P-V for Sample 1 Figure 3: Actual Brayton T-S for Sample 1 Figure 4: Actual Brayton P-V for Sample 2

8 Figure 5: Actual Brayton T-S for Sample 2 Figure 6: Actual Brayton P-V for Sample 3

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version

Access to all documents
Unlimited textbook solutions
24/7 expert homework help

9 Figure 7: Actual Brayton T-S for Sample 3 Figure 8: Actual Brayton P-V for Sample 4

10 Figure 9: Actual Brayton T-S for Sample 4 Figure 10: Actual Brayton P-V for Sample 5

11 Figure 11: Actual Brayton T-S for Sample 5 Ideal Plots:

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version

Access to all documents
Unlimited textbook solutions
24/7 expert homework help

12 Figure 12: Ideal Brayton T-S Figure 13: Ideal Brayton P-V 2. Calculate the thermal efficiency for the Brayton cycle for each engine speed. a. η ?ℎ,???𝑦??? = 1 − 1 ? ? (𝑘−1)/𝑘 Table 2: Thermal Efficiency of Brayton Cycle for Each Engine Speed Sample Thermal Efficiency 1 0.560 2 0.547 3 0.557 4 0.553 5 0.550 Example Calculation Run 1: ? ? = ? 2 /? 1 = 46. 39/2. 6 = 17. 72

13 η ?ℎ,???𝑦??? = 1 − 1 ? ? (𝑘−1)/𝑘 = 1 − 1 17.72 (1.4−1)/1.4 = 0. 560 3. Perform a first law analysis of each section of the CM-14 engine at each engine speed. Table 3: First law analysis of each section at each engine speed 4. Calculate the efficiency of the compressor section and turbine section for each engine speed. This experiment must be carried out with the engine and the flow in stationary condition. To facilitate the capture of data with meaningful value of the efficiency for all the engine stages the mimic diagram has been modified. Table 4: Efficiencies for each speed 5. Calculate the back work ratio for each engine speed.

14 Table 5: Back Work Ratio for each engine speed Back work ratio: ? ?𝑤 = 𝑤 ??𝑀?,𝑖? 𝑊 ??𝑅?,??? Discussion of Results (Charles Taylor) The diagrams for T-S and P-V as shown represent the analytical solution to the actual data for each of the plots made. When these are compared to figures 12 and 13, the ideal P-V and T-S diagrams, many extrapolations can be made. This includes the fact that these plots show a large amount of systematic error within the data, because they show repeated error that manifests in the same way at each engine speed. The thermal efficiency table, Table 2, shows the different thermal efficiency at each engine speed and sample number. The first law analysis of each system for the compressor, combustion and the turbine are represented in the first law work equations shown in table 1. These values are calculated for each dataset within the points 1 and 2 for compressor, 2 and 3 for combustion and 3 and 4 for turbine. The back work ratio is a function of the work outputs for the turbine and the compressor. This is then calculated by dividing these works to achieve a ratio. There are many possible sources of error within this experiment. Based on the data discussed above it is likely that this experiment involves more systematic errors than human errors. This is because most of the errors are repeated as opposed to random, inconsistent errors. Some examples of these errors in the data are the T-S and P-V diagrams when compared to the ideal diagrams. Possible reasons for these systematic

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version

Access to all documents
Unlimited textbook solutions
24/7 expert homework help

15 errors include the software only being the academic version of the data taking program, only performing 1 trial for each sample engine speed, and not performing the experiment in a temperature controlled environment. These factors may have affected the data drastically and systematically throughout the entire experiment. The team’s hypothesis stated that the error will be primarily systematic which is absolutely proven true. The team also hypothesized that the areas without pressure change would have the highest efficiencies, this was true. Conclusion (Charles Taylor ) Based on the data collected within this experiment the team’s hypothesis held true for both statements. The data also showed a large congregation of systematic error within the areas primarily regarding the compression and turbine chambers. These likely had high amounts of error due to the academic level of software used to extract this data from the turbine and compressor. The objective of this experiment was to determine the efficiencies and back work ratios for each of the different engine speeds tested for within the dataset. This was accomplished both in the report and in the experiment itself. The team concludes that if this experiment were to be done again, it is recommended that the team spends more time discussing the theory around finding the efficiencies and the ideal values of the data with the lab guide, professor and TA. This would aid in the team’s expression of the dataset and likely allow them to understand the data which is being reduced more. References ( Khanitha Soeung ) [1] Nourollahi, A. (2024). ME-495 Laboratory Exercise – Number 1 Brayton Cycle In ME Dept, SDSU – Nourollahi. SDSU Publishing