Quick Start

Basic Usage

Running HydDown is as simple as:

python scripts/hyddown_main.py input.yml

where input.yml is your input file in YAML syntax.

Simple Example

Here’s a minimal example for a vessel depressurization calculation:

vessel:
  length: 2.0
  diameter: 0.5
  orientation: "vertical"

initial:
  pressure: 15000000
  temperature: 293.15
  fluid: "Hydrogen"

calculation:
  type: "isentropic"
  time_step: 0.1
  end_time: 100

valve:
  flow: "discharge"
  type: "orifice"
  diameter: 0.01
  discharge_coef: 0.84
  back_pressure: 101325

Save this as input.yml and run:

python scripts/hyddown_main.py input.yml

Streamlit Application

HydDown includes an interactive web interface built with Streamlit:

streamlit run scripts/streamlit_app.py

This provides a user-friendly interface for:

  • Setting up calculations without writing YAML

  • Visualizing results in real-time

  • Comparing with validation data

Available Streamlit Apps

  • streamlit_app.py - Main application

  • streamlit_genapp.py - General purpose calculator

  • streamlit_h2app.py - Hydrogen-specific calculator

  • streamlit_sbapp.py - Stefan-Boltzmann fire scenario

  • streamlit_bdv_sbapp.py - Blowdown valve with fire

Example Files

Example input files for various calculation types are located in:

src/hyddown/examples/

These include:

  • Isothermal filling/discharge

  • Isentropic expansion

  • Isenthalpic throttling

  • Energy balance with heat transfer

  • Fire scenarios

  • Two-phase calculations

  • Relief valve sizing