The empirical modeling of a Lysholm screw expander
This is a description of the development of an engine model for the prediction of mass flow rate, power, efficiency and exhaust quality for a Lysholm Screw Expander at a given set of operating conditions. The testing of an expander having a rotor diameter of 130 mm (5.12 inches) and an expansion ratio of 5.3 was performed with simulated geothermal fluid at an inlet pressure of 0.827 MPa (120 psia). The inlet quality, engine speed and pressure ratio were independently varied to produce a three-dimensional data matrix of 104 data points. Statistical curve fitting methods were adapted to produce equations for mass flow rate and power output in terms of the three variables associated with the data matrix. These explicit equations were combined with a numerical steam table subroutine to produce an engine model. The predictive ability observed during the validation of the model is adequate for use in system modeling, such as a hybrid geothermal energy conversion system. Mass flow rates were predicted to within 3% of the measured values. For most conditions, predictions of power were within 3% of the measured values. The predictions for exhaust quality were within 1/2% of the measured values. Predictions of engine efficiency reflected the combined errors in prediction of power and mass flow rate. The maximum error in efficiency predictions was 1 part in 20.
- Research Organization:
- Mechanical Engineering Department, University of California, Berkeley, California
- OSTI ID:
- 5419552
- Report Number(s):
- CONF-830812-
- Journal Information:
- Proc., Intersoc. Energy Convers. Eng. Conf.; (United States), Vol. 1; Conference: 18. intersociety energy conversion engineering conference, Orlando, FL, USA, 21 Aug 1983
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
HELICAL ROTARY SCREW EXPANDER
MATHEMATICAL MODELS
TESTING
DATA COVARIANCES
EFFICIENCY
EXHAUST SYSTEMS
EXPANSION
FLOW RATE
FORECASTING
GEOTHERMAL FLUIDS
HYBRID SYSTEMS
MASS
ROTARY ENGINES
STATISTICS
THREE-DIMENSIONAL CALCULATIONS
ENGINES
FLUIDS
HEAT ENGINES
INTERNAL COMBUSTION ENGINES
MATHEMATICS
150802* - Geothermal Power Plants- Power Plant Systems & Components