Discussion Overview
The discussion revolves around calculating the fill time for a pressure vessel, focusing on the parameters affecting the mass flow rate and the complexities introduced by pressure differentials during the filling process. Participants explore theoretical and practical aspects of the calculation, including the effects of gas compression and the use of differential equations.
Discussion Character
- Technical explanation
- Debate/contested
- Mathematical reasoning
Main Points Raised
- One participant outlines the parameters known for the pressure vessel and attempts to calculate the fill time using mass flow rate, but finds the result unrealistic.
- Another participant inquires whether the fluid is a gas or a liquid, leading to clarification that it is air at 520R.
- Concerns are raised about whether the initial calculations consider the effects of compression and the pressure differential between the empty tank and the inlet pressure.
- Participants discuss the rapid expansion of gas to fill the tank and the longer time required to reach the desired pressure, indicating a misunderstanding of the initial assumptions.
- One participant expresses the need to calculate the time to pressurize the vessel to 420 psig and questions the necessity of using a differential equation for this calculation.
- Another participant suggests that the flow rate will decrease as the pressure in the tank rises, emphasizing the role of pressure differential in determining flow rate.
- A participant shares a screenshot of their calculations in Mathcad and seeks verification of their validity, expressing doubt about their correctness.
- Discussion includes the consideration of constant mass flow in the case of a screw compressor and the implications for fill time calculations.
- One participant points out a potential error in using SCFM for fill time calculations, suggesting the need to determine the actual fill volume at different pressures or to use ACFM for accurate estimates.
Areas of Agreement / Disagreement
Participants express differing views on the assumptions made regarding gas behavior during filling, the necessity of differential equations, and the appropriate methods for calculating fill time. No consensus is reached on the best approach to solve the problem.
Contextual Notes
Limitations include the dependence on the definitions of flow rates (SCFM vs. ACFM) and the unresolved nature of the mathematical steps involved in the calculations. The discussion reflects varying assumptions about gas behavior and pressure effects.
