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Writer's picturePatrick Law

Pressure Drop in Suction and Discharge



Introduction:

In this project, we focused on calculating the pressure drop in the suction and discharge lines of Pump P-001, a centrifugal pump in a water transport system. The calculation of pressure drops is essential to prevent operational issues like cavitation and to ensure the efficient performance of the pump. The project was guided by structured prompts to ensure a thorough approach, including detailed inputs, assumptions, calculations, and quality control checks. The Python code was employed to validate all results and provide a comprehensive analysis of the system’s performance.



Prompts Used:


Prompt 1 of 5: PRE-PROMPT

The pre-prompt introduces the overall structure of the calculations, providing a clear framework for the process. The GPT focuses on assisting with process engineering calculations, ensuring that every calculation follows a consistent format and adheres to engineering standards.



Enter this first prompt into ChatGPT. This sets the groundwork for calculations by establishing a clear framework to ensure each step adheres to process engineering standards.



Prompt 2a of 5: BACKGROUND, CALCULATION OBJECTIVES

This prompt is tailored to each specific equipment type. In this case, the focus is on a centrifugal pump.

  • Background Prompt:"This project involves determining the pressure drop in both the suction and discharge piping of Pump P-001, a centrifugal pump transporting water. Accurate pressure drop calculations are necessary to avoid issues like cavitation and to maintain efficient operation."

  • Calculation Objectives:

    1. Pressure Drop in Suction

    2. Pressure Drop in Discharge

Prompt 2a of 5

Result



Prompt 2b of 5: INPUTS AND ASSUMPTIONS

This section outlines all the inputs and assumptions used in the calculation, which are unique to the equipment type and project.

  • Inputs and Assumptions Prompt:"The purpose of this section is to list down all the inputs and assumptions used in the calculation."

  • Example Inputs:

    • Fluid Type = Water

    • Density (ρ) = 1000 kg/m³ (Ref: Sigma-Aldrich)

    • Fluid Velocity (V) = 3 m/s (Ref: Assumption)

    • Suction Pipe Length (L_suction) = 20 m (Ref: Assumption)

    • Discharge Pipe Length (L_discharge) = 25 m (Ref: Assumption)

    • Pipe Roughness (ε) = 0.045 mm (Ref: Perry's Chemical Engineers' Handbook)

Prompt 2a of 5

Result



Prompt 3 of 5: CALCULATION

This section handles the calculation of pressure drops using the Darcy-Weisbach equation, ensuring all steps are conducted in metric units and that the intermediate steps are properly documented.

  • Calculation Prompt:"For the calculation of [Pressure Drop in Suction, Pressure Drop in Discharge], the process must be thorough, using Python to validate the results. Print the formula, substitute values, and show all intermediate results."

  • Example Calculation:

    • Formula:ΔP = f (L / D) (ρ * V² / 2)

    • For suction: ΔP_suction = 12.00 kPa

    • For discharge: ΔP_discharge = 15.00 kPa

Prompt 3 of 5 and result


Prompt 4 of 5: QAQC

This step ensures that all calculations are validated by performing a QA/QC check using Python. The prompt requires detailed explanations and verification of the results.

  • QA/QC Prompt:"Double-check and execute all calculations using Python, ensuring a step-by-step process for clarity. Compare the recalculated results with the initial ones."

  • QA/QC Check:

    • Recalculated ΔP_suction = 12.00 kPa

    • Recalculated ΔP_discharge = 15.00 kPa

    • Status: Match for both suction and discharge calculations

Prompt 4 of 5 and result


Prompt 5 of 5: Generate the Final Output

The final output follows a structured template from background to attachments, ensuring the entire process is presented clearly. This includes all calculations and results, along with references and Python code for validation.

  • Final Output Prompt:"Generate the final output following the template [Background to Attachments]. The calculations section should include all the calculations mentioned, and final outputs must be text-based."

  • Final Outputs:

    • Pressure Drop in Suction = 12.00 kPa

    • Pressure Drop in Discharge = 15.00 kPa

Prompt 5 of 5

Python Code


Conclusion:

This project demonstrated the effectiveness of using structured prompts for calculating pressure drops in centrifugal pump systems. By following the five main prompts, from background and objectives to detailed calculations and QA/QC checks, we were able to calculate the pressure drops in both the suction and discharge lines of Pump P-001. The calculations were validated using Python, ensuring consistency and accuracy throughout the process. The results—12.00 kPa for suction and 15.00 kPa for discharge—confirm that the pump operates efficiently and within acceptable parameters, preventing issues such as cavitation.


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