# STEAM - PowerPoint PPT Presentation

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STEAM. STEAM means: S team T raction E ngineering A nalysis M ethod It’s a bit corny, but at least it means something!. What is it? A spreadsheet which can be used to predict: Locomotive Performance: Indicated Output Wheel Rim Output Drawbar Output Steam Consumption

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STEAM

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#### Presentation Transcript

STEAM

• STEAM means:

• Steam Traction Engineering Analysis Method

• It’s a bit corny, but at least it means something!

What is it?

A spreadsheet which can be used to predict:

• Locomotive Performance:

• Indicated Output

• Wheel Rim Output

• Drawbar Output

• Steam Consumption

• Indicator Diagrams

• Exhaust Conditions

Origins

• Started as a means for assessing forces acting on the locomotive frame.

• Evolved to include additional parameters (e.g. steam properties, speed).

• Still “Work in Progress”

How it Works

• Calculates what happens through one complete wheel revolution in 1 Degree increments.

• Uses inputs (valve events, steam chest pressure, cut-off) to generate an Indicator Diagram.

• Calculates net piston force, forces on axleboxes, torque at driving axle, tractive effort and work done through the wheel revolution.

• Inclusion of a speed parameter allows indicated power to be calculated.

• Steam properties allow steam consumption to be calculated.

• Resistance formula allow wheel rim and drawbar outputs to be found.

New Features on Version 4d

• Use of embedded steam tables.

• Improved method of calculating steam consumption.

• A “Generation Steam” Factor which allows locomotives with poorer front end design to be analysed.

• Exhaust Steam temperature calculation.

• Revised resistance calculation.

Validation

Results compared with data from:

• The “Red Devil”

• Rugby Testing Station results

• Swindon test plant results

• Other data from Holcroft / Chapelon etc.

• Dr Pawson’s work with “perform”

Results typically within +/- 5% of Rugby Data and the “Red Devil” (with exceptions!)

IHPs comparable to “perform”

Potential

• A quick and easy to use (once you know it!).

• A simple method by which design changes can be assessed.

• A tool by which locomotive designs can be optimised.

• Calculations are accessible – easy to fudge and look at “what if” scenarios.

• Can be used to assess compounds.

Future Developments

• Boiler and Draughting calculations based on FDCs.

• Inclusion of reciprocating mass calculation.