Jet Engine Component Maps for Performance Modeling and Diagnosis

Abstract

This paper describes an effort to model the performance maps of compressors and turbines (i.e., the relation between mass ow, pressure ratio, and ef ciency), using analytical functions. Analytical functions are tted to the available experimental data using a least-squares-type approach for determining the parameters of the tting function. The success of using a particular function for an application is assessed through a suitably de ned mean error of the model. Apart from presenting the method for setting up these analytical representations, applications to performance modeling and fault diagnosis are discussed. The change in model parameters is used to characterize changes of the engine condition and possibly diagnose occurring faults. The impact of introducing analytical component models into overall engine computer models, replacing a tabulated form of the component maps, is also discussed. NomenclatureF f = ow function, Eq. (18) h t = total enthalpy m Ç = mass ow N = rotational speed, rpm n = nondimensional rotational speed P f = power function, Eq. (18) P t = total pressure T t = total temperature X, Y = transformed values of the map variables x, y = raw values of the map variables ai = parameters of the analytical functions D h t = enthalpy drop in the turbine d = P t /Pt-REF hc = compressor adiabatic ef ciency, total -total hT = turbine adiabatic ef ciency, total -total u = T t /T t-REF i = corrected mass ow, m Ç ? /d u Ï P = compressor pressure ratio Subscripts REF = value at a reference point sl = value at the surge line

Modeling of Turbine Engine Axial-Flow Compressor and Turbine Characteristics

“…This kind of map descriptionpresents the possibility to successfully model maps of different design types. A method of this type has been used by Sieros et al 5 The aim of this study is to describea conceptof modelingthe compressor and turbine characteristics that has been developed specifically for the digital simulation of the transient-state operation of gas-turbine engines. The main innovation is the adaptation of the functions of two variables and original data rescaling.…”

The Need for a Performance Map Based Decision Process

“…The map for spark advance [29] is highly nonlinear and nonmonotonic and visualization of the surface is critical in the development of control strategies. In [30], Seiros et al model the performance maps of compressors and turbines using analytical functions and also discuss their application to fault diagnosis. In [31], Rizzoni and Guzzella describe methodologies for scaling performance maps for the analysis, design and control of hybrid vehicles.…”

Modeling and extrapolating mass flow characteristics of a radial turbocharger turbine

“…Since the Sieros et al model [31] and the Jensen et al model [18] showed relatively bad performances in Fang's study [2], and the Fang and Dai model [2] has a little difficult to conduct fitting procedure because of its extensive computer trial to determine the E, those three models were excluded in the following comparative studies.…”

“…(1) Empirical model Sieros et al [31] introduced a quadratic polynomial expression to approximate the mass flow characteristic,…”