Comment 1 for bug 1989236

I missed putting this in the bug report.
From my code:

// verify_and_correct model

// max steam vrs max speed
damper_factor_manual = boiler_steam_output_max / MPH60; // a factor for damper control that will vary with speed.

blower_steam_usage_factor = (0.04f * 2.20462f / 255) * boiler_steam_output_max / boiler_pressure_max; // kg/sec/psi/control_step

// draft_air multipliers, guess work for now
// natural draft can support 20% of full burn
fire_draft_multiplier = (fire_mass_ideal * 0.2f) / grate_burn_rate_max; // background burn rate
// exhaust, by itself, supplies air for 85% of full burn
exhaust_draft_multiplier = (fire_mass_ideal * 0.85f) / boiler_steam_output_max;
// blower can support 40% of full burn
blower_draft_multiplier = (fire_mass_ideal * 0.4f / 255) / (blower_steam_usage_factor * boiler_pressure_max); // control 0..255

note:
I expect at full steam, the firebox will suffer from excess air.
I expect that because the stack and flues will be designed for efficient operation at a
nomimal steam usage less than the maximum.
The fireman will be expected to close the dampers somewhat.