In the present work, a dynamic model has been developed for the small-scale high-temperature ORC experimental test rig at the LUT University that utilizes waste heat from a heavy-duty diesel engine exhaust. The experimental facility consists of a high-speed Turbogenerator, heat exchanger components such as recuperator, condenser, and evaporator with a pre-feed pump to boost the working fluid pressure after the condensation process constituting a cycle. The turbogenerator consists of a supersonic radial-inflow turbine, a barske type main-feed pump, and a permanent magnet type generator components connected on a single shaft. Octamethyltrisiloxane (MDM) is the chosen organic working fluid in this cycle. Matlab-Simulink environment along with the open-source thermodynamic and transport database Cool-Prop has been chosen for calculating the thermodynamic properties of the dynamic model. A functional parameter approach has been followed for modeling each block component by predefined input and output parameters, aimed at modeling the performance characteristics with a limited number of inputs for both design and off-design operations of the cycle. The dynamic model is validated with the experimental data in addition to the investigation of exhaust gas mass flow regulation that establishes a control strategy for the dynamic model.

Motivated by the urgent need for flexibility and start-up capability improvements of conventional power plants in addition to extending their life cycle, General Electric provides its customers with a product to pre-warm steam turbines using hot air. In this paper, the transient thermal and structural analyses of a 19-stage IP steam turbine in various start-up operating modes are discussed in detail. The presented research is based on previous investigations and utilises a hybrid (HFEM - numerical FEM and analytical) approach to efficiently determine the time-dependent temperature distribution in the components of the steam turbine. The simulation strategy of the HFEM model applies various analytical correlations to describe heat transfer in the turbine channel. These are developed by means of extensive unsteady multistage conjugate heat transfer simulations for both start-up turbine operation with steam and pre-warming operation with hot air. Moreover, the complex numerical setup of the HFEM model also considers the thermal contact resistance (TCR) on the surfaces between vane and casing as well as blades and rotor. Prior to the analysis of other turbine start-up operating modes, the typical start-up turbine process is calculated and validated against an experimental data as a benchmark for subsequent analysis. In addition to heat transfer correlations, the simulation of a turbine start-up from cold state uses an innovative analytic pressure model to allow for a consideration of condensation effects during first phase of start-up procedure.

For the reliable operation of modern gas turbines, Thermal Barrier Coatings (TBCs) need to withstand a wide range of ambient conditions resulting from impurities in inlet air or fuels. A novel deposition model has been developed that enables the prediction of deposition and transport of gaseous species originating from impurities in the gas turbine working media. The successful alignment of conditions in real engines with model results will allow to address the increasing demand for more fuel- and operational flexibility of current and future gas turbines. When analyzing deposition of detrimental hot gas constituents, previous efforts largely focus on the investigation of solid and molten deposit interaction with TBCs. Recent literature and observations in gas turbines indicate that not only liquids can penetrate porous TBCs, but the deposition from gas phase inside of pores and cracks is also an aspect of TBC degradation. To investigate this vapor deposition process, a diffusion model has been coupled with a thermodynamic equilibrium solver. The diffusion model calculates vapor transport of trace elements through pores and gaps in the TBC, where the thermodynamic equilibrium solver calculates local thermodynamic equilibria to predict whether deposition takes place. The model can calculate deposition rates within TBCs by taking into account the chemical composition of impurities in the hot gas as well as pressure, temperature profile in the TBC, and the TBC’s pore structure. Utilizing the model, a wide range of different fuel chemistries can be analyzed to draw conclusions regarding possible effects on TBC lifetime. In this work the model is applied to discuss deposition properties of calcium. In recent literature calcium has — in some cases — been reported to deposit inside of TBCs as pure anhydrite (CaSO 4 ). An actual anhydrite finding in the TBC of a stationary gas turbine blade was reproduced applying the introduced model. The vapor deposition is shown to occur within and on top of the TBC, depending on a number of factors, such as: pressure, temperatures, calcium to silicon ratio and calcium to sulfur ratio.

The formation of water droplets within condensing steam turbines is a complex process that occurs at supersaturated, non-equilibrium conditions and is influenced by the unsteady segmentation of blade wakes by successive blade rows. This is often referred to as ‘wake chopping’, and its effect on the condensation process is the subject of this paper. The practical significance is that thermodynamic ‘wetness losses’ (which constitute a major fraction of the overall loss) are strongly affected by droplet size. Likewise, droplet deposition and the various ensuing two-phase phenomena (such as film migration and coarse-water formation) also depend on the spectrum of droplet sizes in the primary fog. The majority of wake-chopping models presented in the literature adopt a stochastic approach, whereby large numbers of fluid particles are tracked through (some representation of) the turbine flowfield, assigning a random number at each successive blade row to represent the particle’s pitchwise location, and hence its level of dissipation. This study contributes to the existing literature by adding: (a) a comprehensive study of the sensitivity to key model parameters (e.g., blade wake shape and wake decay rate); (b) an assessment of the impact of circumferential pressure variations; (c) a study of the implications for wetness losses and (d) a study of the implications for deposition rates.

Recognizing the attention currently devoted to the environmental impact of aviation, this three-part publication series introduces two new aircraft propulsion concepts for the timeframe beyond 2030. This first part focuses on the steam injecting and recovering aero engine concept. In the second part, the free-piston Composite cycle engine concept is presented. A third publication, building upon those two concepts, presents the project which aims for demonstrating the proof of concept with numerical simulation and test-bench experiments up to a technology readiness level of three. In the steam injecting and recovering aero engine concept, exhaust heat generated steam is injected into the combustion chamber. The humidified mass flow contains significantly more extractable energy than air. Furthermore, the pumping of liquid water up to the necessary pressure requires a magnitude less power than the compression of air, which reduces the internal power demand. Both lead to a noticeable increase in specific power compared to a conventional gas turbine and, foremost, to a significant increase in thermodynamic efficiency. By use of a condenser, installed behind the steam generator, the water is recovered from the exhaust gas-steam mixture. The proposed concept is expected to reduce fuel burn and CO 2 emissions by about 15 % and NO x formation can be almost completely avoided compared to state-of-the-art engines of the same technology level. Moreover, the described concept has the potential to drastically reduce or even avoid the formation of condensation trails. Thus, the steam injecting and recovering aero engine concept operated with sustainable aviation fuels offers the potential for climate-neutral aviation. Based on consistent thermodynamic descriptions, preliminary designs and initial performance studies, the potentials of the concepts are analyzed. Complementarily, a detailed discussion on concrete engineering solutions considers the implementation into aircraft. Finally, the impact on emissions is outlined.

The influence of turbulence modeling approach by means of (U)RANS and LES on the overall modeling of turbulent condensing wet steam flows is investigated using the example of a low-pressure steam turbine cascade. For an accurate numerical treatment of turbulence in presence of shock waves, necessary for predictive scale-resolving computations, a hybrid flux treatment switches between a baseline non-dissipative central flux in energy consistent split form and a shock-capturing upwind flux in shocked regions based on a shock sensor. Condensation is realized by a mono-dispersed Euler-Euler source term model, the equation of state by the highly efficient and accurate SBTL tabulation. The numerical treatment is validated with a decay of homogeneous isotropic turbulence test case containing eddy shocklets. The measurement results of the condensing wet steam cascade are overall much better matched by LES compared to RANS and URANS. Analysis shows that the LES is much better able to account for the inherently unsteady nature of the spontaneous condensation process and its interaction with the trailing edge shock wave structure.

Understanding the phenomenon and quantitative prediction of wet loss, quantitative prediction of erosion are still challenges in ST development. The aim of the actual steam test reported in this paper was to verify the performance of a newly developed ST. Still a comprehensive understanding of the wetness phenomenon is also a significant issue. Therefore, in connection with the actual steam test, efforts were made to develop a method for analyzing the three-dimensional causes of wetness loss and erosion. As the first report on the wet phenomenon analysis performed in this actual steam test, this paper reports wet measurement results and analysis results. In the actual steam testing of a 0.33 scaled steam turbine, wetness measurements were carried out at the third stage (L-1) and the final stage (L-0), and its characteristic wetness distribution was analyzed using our original CFD-code MHPS-NT. This 0.33 scaled steam turbine consists of the final three stages (LP-end) and the inlet steam conditioning stage (total of four stages), and wetness distributions in the blade height-wise were measured using two different wetness probes under several operating conditions. Wetness distribution did not change linearly with changes in ST inlet temperature, but dynamic changes in peak position and shape were observed. From the ST inlet to the exhaust chamber, the generation of fine droplets, the capturing of droplets by the wall surfaces, and the behavior of water films and coarse droplets were comprehensively analyzed using a three-dimensional (3-D) unsteady Eulerian-Lagrangian coupling solver that takes into account non-equilibrium condensation. This CFD code (MHPS-NT) is an improved version of Original-NT developed by Tohoku University. By considering the relative position and structure of the wet probe and blade cascade in CFD, it was found that the wetness is formed remarkable circumferential distribution by the moisture separation of the upstream blade rows and end-walls. The circumferential distribution of wetness can be a factor that makes it difficult to grasp the liquid phase distribution inside the steam turbine as an error factor independent of the accuracy of the optical measurement device. Due to the effects of water droplet capturing, the LP-end outlet wetness at the design point may be underestimated by 21% relative. It is also reported that because the wetness has a distribution in the meridian direction, wetness measurements by the wet probe may contain measurement errors independent of the measurement accuracy.

The heat balance of gas turbine (GT) combustors is used for determining the average Combustor Exit Temperature (CET). It is important for designing the hot parts in this area. Sensor measurements of the CET are nearly impossible due to its high level up to above 1700°C. Therefore it is typically evaluated based on a 1-D cycle calculation, in which the combustor receives compressed air and fuel and it discharges the hot combustion gas at the temperature CET. In the classic approach the fuel heat received in the combustor is evaluated based on the lower heating value (LHV) of the fuel and after the complete combustion the mixture of excess air and combustion products leaves the combustor at the temperature CET, which is calculated based on its specific enthalpy function. So far so simple but this is tricky. The reaction energy is not the LHV but the higher heating value HHV, which includes additionally the discharged energy for condensing the combustion water at ambient temperature. The total heat comes into the flue-gas in the combustor, which is designed for a combustion efficiency of typically 99%+. There is no significant downstream reaction known, which could add the missing difference of HHV-LHV. In GT based power stations condensation is mostly avoided by sufficiently high stack temperature. For methane as a fuel the HHV is around 11% higher than the LHV. Thus the CET derived with the LHV for a given fuel mass flow rate may be underestimated. The method comparison shown below indicates values around 10K. This is a “grey” issue. The intention of this paper is an attempt to understand this practice both technically and historically. Gas turbine catalogues indicate performance data based on burning pure methane. This may have its historic roots in the fact that methane (only Methane, not higher hydrocarbons) burns with oxygen without a change of the specific volume. This simplified the cycle calculation in the sense that combustion could be modelled by adding the LHV to air and methane (assuming an equal temperature) and by calculating the expansion of air and methane separately (corresponding to mixed if no chemical reaction due to the high temperature is assumed) but with the same polytropic efficiency. At ambient temperature this fuel-air mixture is still gaseous and therefore the heat balance of the GT matches exactly with the LHV (used before in the combustor heat balance) because there is no condensation issue. Another feature of the air may compensate the CET mistake partly when using the LHV. It is the effect of dissociation. This increases the specific heat and therefore reduces the calculated CET. In the older time the used specific heat function of air did not include the dissociation effect while nowadays it is mostly included assuming chemical equilibrium. In this paper the good match of a cycle calculation considering the HHV and dissociation with published OEM data will be demonstrated. Indeed this method contradicts existing standards and practices and a further discussion considering the evidence shown below is welcome. In its current development state it allows considering any fuel defined only by the HHV and by its composition with hydrogen to carbon ratio by mass. Additionally it also allows considering high fogging with water injection rates up to several mass % of the air inlet flow rate.

The most relevant quality key numbers for the largest and most efficient Gas Turbine Combined Cycles (GTCC) are not (only) the data published by the original engine manufacturers OEM’s. Additional numbers are here evaluated with educated guesses based on published data of the latest announcements of the “big four OEM’s” [8]. Such data are of interest for potential customers but also for nailing down the current state-of-the-art for all kind of further cycle studies using turbomachinery components and also as a contemporary history record. Making educated guesses means thermodynamic 1D simulation based on additional assumptions for pressure losses and other cycle data, which have a limited influence on the (unpublished) target quality numbers, such as: • Mixed turbine inlet temperature Tmix. This is a key value describing the technology level. It can be derived independently of the (unpublished) TCLA value. It is a quality number for the general cooling design and for the secondary air systems. • Polytropic efficiency of the compressor blading. This number describes the aerodynamic quality of the compressor blading. • Polytropic efficiency of the turbine blading. It describes the quality level of both the blading aerodynamics and of the open air cooling design. • Distribution of the exergy losses within the GT and in the bottoming cycle. The exergy losses describe the remaining opportunities for further improvements in the thermodynamic cycle design. But they also indicate its limits. However already the determination of the Tmix is tricky. It depends on the analysis method and on the fluid data applied. The polytropic efficiency of the turbine blading and the exergy losses will depend both on the used methods and on the Tmix found. Achieving a trustable result therefore requires a transparent and reproducible method. In case of application of the found results for performance prediction of similar cycles the same method has to be applied in order to avoid mistakes. In this paper real gas data with consideration of dissociation in equilibrium are used, while the polytropic efficiencies are determined with an incremental method based directly on the classic definitions of Stodola [3] and Dzung [4]. Therefore the still most used method using semi-perfect gas properties and corresponding formulas is bypassed. In order to keep it as simple as possible the evaluation is limited to base load at ISO ambient condition (15°C, 60% relative humidity, sea level). The fuel is limited to pure methane according to the practice in current catalogue data. The main focus is on the gas turbine with its components. The steam bottoming cycle is captured with its effect on the overall exergy and energy balance of the GTCC, which identifies exhaust and condensation losses.

The Czech Technical University in Prague (CTU) has been conducting both theoretical and experimental research on wet steam for over 50 years. Part of this research has focused on the development of an instrument for measuring the structure of the liquid phase of wet steam — an optical extinction probe. The measurements of the wet steam structure using our optical extinction probe take place in operative steam turbines. Due to the non-negligible interaction of the probe with the flow field in its vicinity, the wet steam parameters within the probe measuring space change. This probe-flow field interaction (PFFI) negatively affects the accuracy of the measurement of the liquid phase structure. This paper presents partial results of our research into the interaction between the optical probe and the surrounding flow field. Particularly, it is the result of CFD simulations of wet steam (WS) flow in the low-pressure section of a 1000 MW nuclear plant steam turbine, in which the probe has been used repeatedly. In the simulations we consider, non-equilibrium condensation allows for the observation of the formation and development of the liquid phase within the turbine. The influence of PFFI on the liquid phase structure is evaluated by a coefficient called the Probe Influence Factor (PIF). In this work, the PIF values are presented for 3 varying traversing positions of the probe along the L-1 stage turbine blade. The use of the PIF to analyse the experimental measurement results is also discussed. The second part of the paper deals with the possibility of modifying the shape of the probe measuring head. Based on detailed analysis of the CFD simulations of PFFI, modifying the shape of the probe is proposed to reduce this interaction. The benefit of this change is evaluated using CFD simulations. Comparisons between the PIF coefficients of the original and modified optical probes indicate that modifying the shape may reduce the PFFI influence on experimental measurements.

Conventional power plants are obliged to compensate for the fluctuations in power generation, due to the rising amount of renewable energies, to ensure grid stability. Consequently, steam turbines are more frequently facing load variation and startup/shut-down cycles leading to an increase of thermal stress induced by phase change phenomena. The review of existing test facilities providing measurement data of heat transfer coefficients influenced by multiphase phenomena, such as surface wettability and dry-out, revealed the necessity for a new measurement application. This paper presents the design of the Experimental Multi-phase Measurement Application “EMMA” to generate the required conditions in combination with an academic turbine housing geometry. The performed investigations are focused on the local distribution of heat transfer coefficients (HTC) and the surface wettability affected by phase change phenomena. Two main film formation mechanisms can be observed, depending on the thermal gradient between the fluid and the wall. These are a) saturated/superheated steam in contact with a sub-cooled wall leading to film-wise/drop-wise condensation and b) primary condensed wet steam droplets depositing on a superheated wall, leading to evaporation. Both, the liquid film and the local heat transfer are measured simultaneously. An overview of applicable thickness measurement methods for transparent liquid films is given and the applied optical measurement system is further described. Moreover the HTC measurement methods are presented considering the occurring case of phase change.

From the polytropic compression work formula, we can find that the consumed polytropic work will reduce with the decrease of inlet temperature while compressing the refrigerant to the same compression ratio. However, the refrigerant may condense if the inlet temperature is low enough. Though the principle that the acceleration of fluid may result in condensation has been proved by numerical simulations and experiments, and the liquid formation inside the supercritical carbon dioxide (SCO2) centrifugal compressor has been widely studied, there is still not a user-friendly method to predict whether the inlet condition may cause liquid formation inside the compressor. The fluid flow in the space near the blade suction face of the leading edge (SNSL) is assumed to the similar flow in a converging nozzle when the mass flow is larger enough; the fluid impinges on the suction surface of blades, and the absolute velocity of fluid will not be greater than sound velocity. The fluid turns to impinge on the pressure surface with the decrease of mass flow rate, which is similar to the flow in a converging-diverging nozzle, and the maximum absolute velocity in the SNSL may be greater than the sound speed. A method is proposed to predict the lowest inlet temperature of refrigeration centrifugal compressor to avoid phase change, which is called the limit temperature. The predicted lowest temperature shares the same trend with the numerical results. The condensation will occur inside the compressor when the inlet temperature is lower than the limit inlet temperature. The lowest temperature will first increase and then decrease as the mass flow increases, which should be taken into account while designing a refrigeration centrifugal compressor or adjusting the operating condition.

This study investigates the applicability of an Euler-Lagrange approach for the calculation of nucleation and condensation of steam flows. Supersonic nozzles are used as generic validation cases, as their high expansion rates replicate the flow conditions in real turbines. Experimental and numerical validation data for these nozzles are provided by the International Wet Steam Modelling Project of Starzmann et al. (2018). In contrast to most participants of that project, an Euler-Lagrange approach is utilized for this study. Therefore, the classical nucleation theory with corrections and different droplet growth laws is incorporated into the Discrete Phase Model of ANSYS Fluent. Suggestions for an efficient implementation are presented. The Euler-Lagrange results show a good agreement with the experimental and numerical validation data. The sensitivities of the Euler-Lagrange approach to modelling parameters are analysed. Finally, an optimal parameter set for the calculation of nucleation and condensation is proposed.

In this paper we present a turbomachinery density-based CFD solver optimized for CPUs as well as GPUs, which accounts for complex thermodynamics including non-equilibrium condensation and two-phase flow, making extensive use of tabulation techniques. The two-phase flow is treated by means of the mono-dispersed Source-Term Euler-Euler model. The non-equilibrium wet-steam model is validated in classical nozzle test cases and its application in turbomachinery configuration is demonstrated in a well-documented steam turbine cascade in the context of classic RANS modeling. Finally, the LES-solver performance and scalability, together with its accuracy, are assessed and discussed on the basis of the well-known and theoretically relevant experiment by Comte-Bellot and Corrsin. For both, standard RANS computations, where an upwind schemes has been adopted, as well as for the LES computations, where a central scheme in skew-symmetric form has been employed, the solver shows remarkable computational speed and accuracy for non-ideal gas applications, rendering it suitable for more complex LES computations in steam turbine flows.

There is increasing interest in supercritical CO 2 processes, such as Carbon Capture and Storage, and electric power production, which require compressors to pressurize CO 2 above the critical point. For supercritical compressor operation close to the critical point there is a concern that the working fluid could cross into the subcritical regime which could lead to issues with compressor performance if condensation was to occur in regions where the fluid dropped below the saturation point. Presently, the question of whether there is sufficient residence time at subcritical conditions for condensation onset in supercritical CO 2 compressors is an unresolved issue. A methodology is presented towards providing a validated simulation capability for predicting condensation in supercritical CO 2 compressors. The modeling framework involves the solution of a discrete droplet phase coupled to the continuum gas phase to track droplet nucleation and growth. The model is implemented in the CRUNCH CFD ® Computational Fluid Dynamics code that has been extensively validated for simulation at near critical conditions with a real fluid framework for accurate predictions of trans-critical CO 2 processes. Results of predictions using classical nucleation theory to model homogeneous nucleation of condensation sites in supersaturated vapor regions are presented. A non-equilibrium phase-change model is applied to predict condensation on the nuclei which grow in a dispersed-phase droplet framework. Model validation is provided against experimental data for condensation of supercritical CO 2 in a De Laval nozzle including the Wilson line location. The model is then applied for prediction of condensation in the compressor of the Sandia test loop at mildly supercritical inlet conditions. The results suggest that there is sufficient residence time at the conditions analyzed to form localized nucleation sites, however, droplets are expected to be short lived as the model predicts they will rapidly vaporize.

This study presents the results of measurements in an industrial steam turbine test rig operated at the Institute of Thermal Turbomachinery and Machinery Laboratory (ITSM) in Stuttgart, Germany. In order to ensure safe operation over a wide range of operating conditions the last and penultimate rotor blade rows of this turbine feature Part-Span Connectors (PSC). The PSC provide additional coupling and mechanical damping during operation, however, they present a major obstacle to the flow, thus causing additional aerodynamic loss. The focus of the present work is on the aerodynamic impact of the PSC on the flow field of the last stage. To capture this impact, an extensive measurement campaign over a wide range of operating points was performed using two last blade row configurations that are identical with regard to the blade design, except for the fact that one features free-standing blades while the second is equipped with PSC. A performance assessment of these two configurations based on detailed probe measurements and overall turbine efficiency is presented. Additionally, a detailed comparison of 3D CFD-results employing an equilibrium steam (EQS) model and a non-equilibrium steam (NES) model for both configurations is shown with good agreement to the test data. However, comparing the two models reveals major differences whenever there is condensation occurring close to the evaluation plane, thus the advantage of applying the NES model is presented.

Existing research has demonstrated the viability of supercritical carbon dioxide as an efficient working fluid with numerous advantages over steam in power cycle applications. Selecting the appropriate power cycle configuration for a given application depends on expected operating conditions and performance goals. This paper presents a comparison for three indirect fired sCO 2 cycles: recompression closed Brayton cycle, dual loop cascaded cycle, and partial condensation cycle. Each cycle was modeled in NPSS with an air side heater, given the same baseline assumptions and optimized over a range of conditions. Additionally, limitations on the heater system are discussed.

Supercritical carbon dioxide (sCO 2 ) power cycles have the potential to offer a higher plant efficiency than the traditional Rankine superheated/supercritical steam cycle or Helium Brayton cycles. The most attractive characteristic of sCO 2 is that the fluid density is high near the critical point, allowing compressors to consume less power than conventional gas Brayton cycles and maintain a smaller turbomachinery size. Despite these advantages, there still exist unsolved challenges in design and operation of sCO 2 compressors near the critical point. Drastic changes in fluid properties near the critical point and the high compressibility of the fluid pose several challenges. Operating a sCO 2 compressor near the critical point has potential to produce two phase flow, which can be detrimental to turbomachinery performance. To mimic the expanding regions of compressor blades, flow through a converging-diverging nozzle is investigated. Pressure profiles along the nozzle are recorded and presented for operating conditions near the critical point. Using high speed shadowgraph images, onset and growth of condensation is captured along the nozzle. Pressure profiles were calculated using a one-dimensional homogeneous equilibrium model and compared with experimental data.

In many supercritical CO 2 cycle implementations, compressor or pump inlet conditions are relatively near the two-phase region. Fluid acceleration near the compressor inlet can result in the potential for condensation or cavitation at the inlet. Despite potential mitigating effects or evidence in the literature, potential two-phase operation is a high-risk condition and may not be recommended for high-reliability system design. This paper presents a summary of the existing literature documenting inlet phase change in sCO 2 , and presents an analysis of required conditions to avoid phase change as a function of inlet pressure, temperature, and Mach number. Static conditions at the inlet are calculated based on the real gas approach documented in ASME PTC-10, Appendix G. In addition, various total-to-static iteration challenges are discussed and avoided through solution of the inverse problem to convert limiting static conditions at saturation to the full range of limiting total conditions for various Mach numbers up to 1.0. The results show that a threshold total temperature exists above which phase change cannot occur, ranging from 31.1 to 66.95 °C and increasing with Mach number. Lower temperatures below this threshold may also avoid phase change depending on the total pressure. The documented results are useful as a reference for use by cycle designers to impose design limits that minimize risks associated with two-phase flow in the compressor.

This paper proposes an approach to construct a nonlinear dynamic model of a whole turbofan engine using the static condensation technique. Nonlinear dynamic behavior of the engine is described by a matrix differential equation, where the right side of the equation represents unbalance load and contact loads between the blades and casings, low-pressure (LP) shaft and high-pressure shaft. Elements of the matrices are calculated by static condensation of three-dimensional finite element models of rotors, casings, engine mounts, and wing attachment system. On the basis of the proposed approach, a model of the entire engine was constructed. The model considered contact interactions as well as effects associated with both instantaneous application of the unbalance load and the passage of the LP rotor through the critical rotational speed during the deceleration phase. The model has a modular structure that allows for the easy replacement of individual components and analysis of the various engine structural frame options. The results of engine structural frame load calculations after a fan blade-out event and during deceleration of the rotors to windmill mode are presented in this paper. In addition, the influence of the flexibility of fan supports, blade wheel nonlinear radial stiffness, and slowdown rates of rotors on load magnitudes are analyzed.