HP Stage Research Articles

Dual-objective optimization of a novel hybrid power generation system based on hydrogen production unit for emission reduction

In this study, a biomass based power generation system is proposed. This system includes a BIG (BIG) system to produce syngas, a proton exchange membrane (PEM) type fuel cell (FC), a gas turbine (GT), and an organic Rankine cycle (ORC). In order to evaluate the system function, first a parametric study is conducted and the effect of the design variables on the production power, exergy efficiency, and the total cost rate (TCR) of the system is investigated. Design variables include biomass moisture content, gasification temperature, compressor pressure ratio, air heat exchanger temperature difference, pressure of FC, current density of FC, LP Stage PPTD, and HP stage pressure. It is observed that the determining factors in the TCR of the system are more affected by the cost of the gasifier and PEM FC system. It is also observed that the ORC plays a greater role in recovering wasted heat and generating power compared to GT. Finally, it is observed that in optimal operating conditions, the exergy efficiency of the system are 33.19% and TCR is 693 $/h, respectively.

Numerical Investigation of Unsteady Combustor Turbine Interaction for Flexible Power Generation

AbstractWith the growing importance of regenerative power generation and especially of a hydrogen-based economy, the full potential of gas turbines of the smaller output class (<10 MW) can be ideally exploited to provide peak coverage of the energy need whilst stabilizing the electric grids in the mid- and low-voltage range. Such machines can be typically started in a relatively short time (similarly to aero engines) and are capable, at the same time, of delivering dispatchable power-on-demand. A safe, stable and profitable operation under highly unsteady conditions poses renewed challenges for an optimal thermal management (especially in the HP stages) as well as control and surveillance of the machines. The understanding and hence predictability of the propagation of the temperature inhomogeneities originating at the combustor outlet remains hence a primary objective of current research, as persistent distortion patterns could be adopted at the turbine exhaust as diagnostic indications of a malfunction of the combustor, for example. In the present study, low-frequency disturbances introduced by a periodic load variation have been simulated and superimposed to the inhomogeneous, unsteady flow entering a three-stage, high-pressure industrial gas turbine fed by a can-type combustion chamber comprising six silo-burners. The effects of the unsteadiness realized at the combustor exit have been investigated by means of Detached Eddy Simulations, whereby a density-based solution approach with detailed thermodynamics has been employed. The periodic disturbances at the turbine inlet have been obtained by means of an artificially generated, unsteady field, resulting from a two-dimensional snapshot of the flow field at the combustor exit. Also, a combustor failure has been mimicked by reducing (respectively increasing) the mean temperature in some of the turbine inlet regions corresponding to the outlet of two burners. The propagation and amplitude changes of temperature fluctuations have been analyzed in the frequency domain. Tracking of the temperature fluctuations' maxima at the lowest frequencies revealed characteristic migration patterns indicating that the corresponding fluctuations persist with a non-negligible amplitude up to the last rows. A distinct footprint could also be observed at the same locations when a combustor failure was simulated, showing that, in principle, the early detection of combustor failures is indeed possible.

Combined phase diagram modelling and quartz‐in‐garnet barometry of HP metapelites from the Kamieniec Metamorphic Belt (NE Bohemian Massif)

AbstractThe Kamieniec Metamorphic Belt belongs to the Variscan Belt of Europe as the NE part of the Bohemian Massif. It comprises a supracrustal succession dominated by micaschists that has not been yet recognized as a high‐P, low‐T (HP–LT) metamorphic unit. Our work demonstrates the significance of metapelites in the study of HP metamorphism of the NE part of the Bohemian Massif. To reconstruct the P–T history of the Kamieniec Metamorphic Belt, we have investigated three samples using independent geothermobarometric techniques including phase diagram modelling, Si4+ content in white mica and quartz‐in‐garnet elastic barometry. Two samples contain mineral assemblages bearing a record of HP metamorphism followed by an LP event. The oldest assemblage is mostly preserved in the first generation of garnet and it comprises phengitic white mica and rutile. In one of the investigated samples, we also recognized chloritoid and inferred pseudomorphs after lawsonite composed of quartz, clinozoisite associated with margarite. The third of the investigated samples is strongly retrogressed and only contains the relics of phengitic white mica. All three samples contain a younger mineral assemblage comprising white mica with low Si4+ content and ilmenite. Mineral equilibria modelling indicates the P–T conditions of the HP event culminated at ~15.5–18 kbar and ~470–570℃, while the LP episode occurred at ~5–7 kbar and ~530–570℃. The Raman shift measured in quartz inclusions in garnet in samples with a well‐preserved record of the HP stage points to their entrapment at pressures between 11 and 16 kbar. The quartz inclusions within the strongly retrogressed micaschist sample exhibit Raman shifts corresponding to the LP episode at ~5–8 kbar. Discrepant results obtained for one of the samples are discussed in detail. Our investigations show that the supracrustal succession of the Kamieniec Metamorphic Belt contains a record of HP–LT metamorphism typical for subduction systems. A recently established tectonic model for the crystalline complexes exposed in the Bohemian Massif suggests that they were formed via the collision of the Saxothuringian, Teplá–Barrandian, and Brunovistulian domains. Therefore, we interpret the Kamieniec Metamorphic Belt as representing fragments of the Saxothuringian crust that experienced cold extrusion from below the Teplá–Barrandian domain in front of the rigid Brunovistulian indenter.

Petrological and Lu–Hf age constraints for eclogitic rocks from the Pam Peninsula, New Caledonia

We report new petrological and geochronological data for eclogitic rocks of the Pouébo Eclogite Mélange (PEM) in the New Caledonian high-pressure/low-temperature (HP/LT) belt. Pseudosections were calculated to link newly determined Lu–Hf dates with P-T conditions corresponding to garnet growth, which started on the prograde path and continued into the eclogite facies to approximately 560 °C and 2.05 GPa, coinciding with omphacite formation. The Lu–Hf garnet dates of 38.27 ± 0.14, 36.5 ± 0.7, and 38.42 ± 0.15 Ma are weighted towards the early part of the garnet growth interval, and thus represent maximum ages of eclogite-facies conditions. These dates are indistinguishable from those reported earlier from Ar–Ar in white mica, which had been interpreted as cooling ages, and they are about 6 Myr younger than those from U–Pb in metamorphic zircon, which had been previously considered to date peak eclogite-facies metamorphism at 44 Ma. The new Lu–Hf dates overlap with Rb–Sr white mica ages of nearby metasomatic veins related to the blueschist-to-eclogite transition. The Lu–Hf and Rb–Sr data imply that eclogite-facies metamorphism in parts of the PEM lasted at least until 38 Ma and is thus younger than previously suggested. This prograde, near-peak event cannot be reconciled with concurrent (41–36 Ma) cooling previously inferred from the Ar–Ar dates. We conclude that both the 38.4–36.5 Ma Lu–Hf and Rb–Sr dates as well as similar Ar–Ar results record near-peak conditions, while the 44 Ma U–Pb zircon rims probably are related to prograde mineral reactions. The HP stage is followed by rapid exhumation and cooling at minimum rates of ~0.7 cm/yr and ~50 °C/Myr.

Theoretical and experimental investigation of the pressure ratio distribution and the regulation strategy of a two-stage turbocharging system for various altitudes operation

Fixed two-stage turbocharging system matched at high altitude leads to engine performance deterioration at low altitudes due to unreasonable pressure ratio distribution between two stages. In this paper, a thermodynamic model of regulated two-stage turbocharging system is established. Theoretical analysis shows the pressure ratio distribution should lean towards a turbocharger with greater efficiency, and the high-altitude operation intensifies the role of HP stage. Experiments are conducted on an environment simulation test bench. Then, the optimal pressure ratio distribution and ETAR at various altitudes are proposed. Experiment results demonstrate that the turbocharging system boosts sufficient intake air with the optimal ETAR. Compared to that with the fixed turbocharging system, the maximum increment of the overall efficiency is 9.3 % at 0 m and attains 1.5 % at 3000 m. Consequently, the output torque is 100 % recovered below 3000 m, and it exceeds 91 % at 4500 m. Moreover, the optimal ETAR reduces the BSFC under low altitude conditions.

HP tectono‐metamorphic evolution of the Internal Piedmont Zone in Susa Valley (Western Alps): New petrologic insight from garnet+chloritoid‐bearing micaschists and Fe–Ti metagabbro

AbstractNew petrologic data from meta‐ophiolites exposed in a relatively poorly known sector of the Western Alps (i.e. Susa Valley, Internal Piedmont Zone) are reported. Garnet+chloritoid‐bearing phengitic micaschist and Fe–Ti metagabbro preserving eclogite facies assemblages have been investigated in detail to constrain the HP tectono‐metamorphic evolution of meta‐ophiolites in the study area. Microstructural investigations allowed to identify different assemblages related to different tectono‐metamorphic stages, whose pressure–temperature (P–T) conditions of the HP stages were constrained using the pseudosection modelling approach combined with multi‐equilibrium thermobarometry. Four main metamorphic stages have been recognized: (a) an Alpine peak‐P stage (M1a), which reached the HP–UHP eclogite facies boundary (P = 25–29 kbar, T = 460–510°C); (b) a slightly prograde decompression stage (M1b), still under eclogite facies conditions (P = 21–25 kbar, T = 500–530°C); (c) a greenschist facies re‐equilibration stage (M2); (d) a nearly isobaric late heating stage (M3), developed at the boundary between greenschist‐ and amphibolite facies conditions. The new P–T path inferred for the HP phases recorded by the studied meta‐ophiolites is compatible with that reported from other meta‐ophiolite units in the Western Alps, that is, the Zermatt–Saas ophiolite to the north and the Monviso ophiolite to the south, confirming that subduction of the Tethys oceanic lithosphere occurred at similar P–T regimes all along its length. The comparison with the tectonic evolution of the adjacent Dora Maira continental crustal unit suggest that the early exhumation of eclogitized oceanic crust likely occurred along the plate interface in the subduction channel, without the buoyancy contribution of continental crust.

Numerical Study of Entropy Wave Evolution within a HPT Stage

Component reciprocal interaction and aero-thermal coupling are critical aspects in modern turbomachinery design. Combustors and highpressure turbine (HPT) interaction is extremely critical due to the compact and lightweight system design. In this context, computational and experimental analyses are thus necessary to study the interaction of the high temperature gas coming from combustor systems and entering the turbine in order to avoid engine mis-operations and to lower the indirect core noise generation. This paper presents a numerical study of pulsating temperature distortion (entropy wave) evolution within a high pressure turbine stage. Four different clocking positions between the 11 temperature spots and the 22 stators have been studied. The numerical results, obtained by URANS computations (TRAF code) and by a dedicated post-processing based on Fourier coefficients, have been compared with experimental measurements coming from the Laboratorio di Fluidodinamica delle Macchine (LFM) of the Politecnico di Milano (Italy) where the HP stage rig is located. The excellent agreement between numerical results and experimental acquisitions confirms the accuracy of the numerical approach. Such results also suggest recommendations for the thermal design of the rows and are the main prerequisite for the study of the indirect core noise generation.

Cretaceous high-pressure metamorphism and low pressure overprint in the Sistan Suture Zone, eastern Iran: Additional temperature estimates for eclogites, geological significance of U-Pb zircon ages and Rb-Sr constraints on the timing of exhumation

The Sistan Suture Zone, eastern Iran, includes blocks and lenses of eclogite-, blueschist- and/or epidote amphibolite-facies rocks that provide an excellent opportunity to examine the exhumation history of oceanic HP/LT rocks and their retrograde derivatives. Zr-in-rutile thermometry of eclogites corroborates previous interpretations suggesting metamorphic temperatures of ca. 550–600°C during the HP stage in the Sistan area. Flat HREE distribution patterns and Ti-in-zircon temperatures of ca. 500–600°C document that zircon in eclogite is of metamorphic origin. REE patterns of zircon from felsic meta-igneous rocks do not allow to distinguish between a magmatic or metamorphic origin, but relatively low temperatures indicated by Ti-in-zircon thermometry (ca. 500–600°C) and the close similarity of zircon (U–Pb) and white mica (Rb–Sr, Ar–Ar) ages favor a metamorphic zircon origin. Previously published isotopic ages of the felsic rocks cannot unambiguously be linked to the eclogite- and/or blueschist-facies P–T conditions due to the absence of unequivocal mineralogical and petrological evidence. Instead, these rocks may record contemporaneous metamorphic processes that took place at a different depth within the subduction complex, or may indicate active ridge subduction and/or melt formation in the subduction zone at relatively low pressures. Biotite-based internal Rb–Sr isochrons of newly dated epidote amphibolite and biotite-albite gneisses indicate ages of ca. 74–80Ma, either dating fluid-infiltration-induced formation of biotite during relatively fast uplift, or the time of final passage through the effective biotite closure temperature. Rb–Sr ages of phengite from both an epidote amphibolite and a biotite-albite gneiss yield ages that correspond to the HP/LT stage. This outcome, combined with textural evidence for derivation from eclogitic precursors documents that white mica ages of some strongly overprinted Sistan rocks are compromised by inheritance and do not record later exhumation.

Effect of grooved cooling passage near the trailing edge region for HP stage gas turbine blade - a numerical investigation

Gas turbines have become one of the most important prime movers especially in aircraft propulsion, land-based power generation, and industrial applications. Cooling of gas turbine blades is a major consideration because HP stage blades are subjected to high temperature working conditions. Several methods have been suggested in the past for the cooling of HP stage blades. The main objective of the present work is to study the effect of grooved cooling passages with different geometric shapes for the groove. This method of cooling is specifically useful for cooling the blades near the trailing edge region. In an earlier work by the present authors, optimised helicoidal cooling duct geometry with circular cross-section was proposed and same technique has been incorporated in the present work for augmented cooling of the leading edge region. The analysis is carried out for different types of groove configuration to assess their cooling performance in terms of their cooling efficiency. The major finding of this work is that the cooling duct provided with buttress shaped grooves results in better cooling of the HP stage gas turbine blade.

Thermo-Structural Investigation of Gas Turbine Blade Provided with Helicoidal Passages

By having helicoidal shape for the cooling passage, it is possible to provide more surface area for cooling per unit passage length. In addition to this, by providing turbulators within the helicoidal passages, it is possible to augment an increase in heat transfer from the blade surface to the cooling fluid. Since FSI is the objective of this analysis, the blade loading corresponding to the static pressure as well as temperature field on the blades surfaces are obtained using CFD run. The output results are then used as structural boundary condition to solve FSI, using finite element method. The present work brings out thermal and structural distortion of the HP stage gas turbine blade. A parametric approach is used for varying the cooling passage geometry to optimize the cooling process. It can be concluded from FSI analysis that circular helicoidal cooling passage (4 mm Φ) of pitch 6 mm with turbulators of size e/D = 0.08 with rib thickness 0.75mm effect in improved cooling properties and in turn reduce structural deformation.

Effect of grooved cooling passage near the trailing edge region for HP stage gas turbine blade -A numerical investigation

Effect of grooved cooling passage near the trailing edge region for HP stage gas turbine blade -A numerical investigation

Valle d'Aosta section of the Sesia Zone: multi-stage HP metamorphism and assembly of a rifted continental margin

The spectrum characteristic of the EMC ranges from eclogites (containing omphacite and/or jadeite, garnet, phengite, glaucophane, zoisite, chloritoid, rutile) to phengite schists, calcschists, and marbles, as well as a variety of orthogneisses. Despite the intense polyphase deformation and HP-metamorphic recrystallization, it is possible in some locations to recognize pre-Alpine characteristics in some of the protoliths. For instance, two types of felsic orthogneiss can be distinguished in the Aosta Valley, one derived from Permian granitoids (with local preservation of intrusive contacts, magmatic inclusions, leucocratic veins and other magmatic structures; Stop 3), the other derived from pre-Variscan leuco-monzogranite, such as the building stone mined at the “Argentera” quarry near Settimo Vittone / Montestrutto (Stop 2; so-called “Verde Argento” contains jadeite, phengite, K-feldspar, quartz). Polycyclic and more rarely monocyclic metasediments contain evidence of a complex Alpine PTDt-evolution, locally including relics of their prograde history from blueschist, one or more stages at eclogite facies. Recent petrochronological studies have dated this HP-evolution of the Sesia Zone in some detail. In the area visited, clear evidence of HP-cycling has been identified in one km-size tectonic slice (Stop 1), but not in adjacent parts of the EMC, indicating “yo-yo tectonics”. Partial retrogression and attendant ductile to brittle deformation of the HP-rocks is evident in one of the outcrops (Stop 4). Apart from the four localities in the Sesia Zone, a final outcrop introduces HP-rocks of the adjacent Piemonte oceanic unit, specifically calc-schists and ophiolite members of the “Zermatt-Saas” zone. The hilltop outcrop (Stop 5) displays foliated antigorite schist with peridotite relics (clinopyroxene, spinel) containing lenses derived from doleritic dykes. These fine-grained metarodingites and the folded veins containing Mg-chlorite and titanoclinohumite within serpentinite once again indicate equilibration under low-temperature eclogite facies conditions. However, these units reached that HP stage more than 20 Ma after the youngest eclogite facies imprint recognized in the Sesia Zone. Despite nearly half a century of intense study in the Sesia Zone, the complex assembly of its HP-terranes and their relation to more external parts of the Western Alps remains incompletely understood. This field guide merely introduces a few of the classic outcrops and discusses some of the critical evidence they contain, but it could not incorporate details on each stage of the evolution recognized so far.

Study of the Influence of Ceramic Thermal Coating on the Mechanical Resistance of the Blades of Aircraft Engines

Abstract In order to prevent these undesirable effects of the high temperatures, two methods are used for protecting the gas turbine blades: cooling of the blades with air from the compressor of turboengine and application of a ceramic thermal barrier coating. The paper analyzes the influence of air flow holes and of the thermal barrier coat on distribution of stresses in a HP stage blade of a turboengine. Blade with and without cooling air holes and thermal barrier coating is considered. The reference model is the blade from HP stage of the EJ 200 turbofun engine, which equips the military aircraft Eurofighter Typhoon. The finite element analysis was done made using the ANSYS 13 program. The ceramic material for thermal barrier coating is ZrO2/20%Y2O3.

Aerodynamic Performance Research of Chordwise Swept Blade Cascade HP Stage at Off-design Condition

In order to research the chordwise swept cascade stage control mechanism for internal flow field under the off-design condition, the 600 MW supercritical steam turbine HP rotor and static blades were selected as prototypes. The chordwise fore-swept cascade stage and chordwise aft-swept cascade stage were achieved with 30% blade height and 20°, -20° swept angle respectively. The three cascades passage flow numerical simulation was conducted by CFD software. The computed results indicated that the degree of reaction and isentropic efficiency of the three cascade stages were changed very little in the scope of 70~120% design flux and decreased sharply when the inlet flux was less than 50% design flux. On the whole, chordwise fore-swept cascade stage had the best aerodynamic performance.

Design and Analysis of High-pressure Casing of a Steam Turbine

Contact pressure and pretension in bolts-analysis has been made easier in recent years due to the availability of high computational capabilities and flexibility in the computational methods using finite element analysis. In the present work, one such analysis is carried out blending the hand calculations and steady-state finite element analysis to evaluate the contact pressure in a high pressure steam turbine casing. The work involves design considerations, design checks, validation and sensitivity analysis to achieve the design criteria to fulfill the structural requirements for mechanical integrity. During the last several years the primary changes to the design of steam turbines have focused on improving their efficiency, reliability and reducing operating costs. Siemens Power Generation, for example, has improved the overall efficiency and availability of its steam turbines by decreasing the steam flow energy losses in each of the steam turbines components. The steam turbine unit largely influences the efficiency and reliability of power stations. Any improvement in the design of steam turbine enables more efficient use of fuel and results in reduced cost. The high pressure steam at 565°C and 156bar pressure passes through the high pressure turbine. The exhaust steam from this section is returned to the boiler for reheating before being used. On leaving the boiler reheater, steam enters the intermediate pressure turbine at 565°C and 40.2bar pressure. From the intermediate pressure turbine, the steam continues its expansion in the three Low pressure turbines. The steam entering the turbine is at 306°C and 6.32bar. To get the most work out of the steam, the exhaust pressure is kept very low. The casing thus witnesses, energy of the steam turned into work in HP and IP stages. So, the design of the casing is a very important aspect.

Megacrysts of kyanite from Baranec Mt., Western Tatra Mountains, Slovakia

Abstract Large crystals of kyanite (<15 cm in size) occur in quartz segregations in Paleozoic gneissses on Baranec Mt., Western Tatra Mountains, northern Slovakia. Blue kyanite crystals coexist with quartz and plagioclase. The kyanite contains inclusions of apatite, monazite. gamet, rutile and biotite and overgrowths of retrograde sillimanite. muscovite and biotite. The kyanite crystals are the largest found up to now in the Tatra crystalline massif or in the other Western Carpathians crystalline cores. Kyanite. with the co-existing mineral assemblage, is indicative of a HP stage duiing Hercynian metamorphism of the Western Tatra Mountains.

Computational Conjugate Heat Transfer Analysis of HP Stage Turbine Blade Cooling: Effect of Turbulator Geometry in Helicoidal Cooling Duct

In a bid to improve turbine entry temperature for maximizing the thermal efficiency of the HP stage gas turbine blade,an attempt is made in this paper to compare the performance of helicoidal ducted blade cooling with turbulator of different geometric proportion. It is found from analysis that there is significant improvement in cooling characteristics for turbine blade with turbulator geometry having larger e/D ratio. Also it is found from analysis, performance is vastly improved for greater thickness of turbulator geometry.

P–T Alpine metamorphic evolution of the Monte Rosa nappe along the Piedmont Zone boundary (Gressoney Valley, NW Italy)

The pseudosection modelling of two chemical systems (both metabasic and metapelitic) allowed to reconstruct the exhumation P–T path followed by the southern slope of the Monte Rosa nappe (Upper Gressoney Valley) during the Alpine orogenesis. The metamorphic evolution of the polymetamorphic basement complex from the Monte Rosa nappe is marked by texturally distinct mineral assemblages, defining four Alpine metamorphic stages (M1 to M4) reflecting a sequence of different P–T conditions. Well preserved eclogitic boudins (M1 and M2 assemblages) were investigated to reconstruct the HP history related to the subduction phase, while re-equilibrated metapelites allowed to infer the P–T conditions attained during the development of the regional foliation (M3 and M4 assemblages). The HP stage (M1) occurred at 550–570°C and 24–27kbar and is characterised by the assemblage Omp+Grt+Lws+Phe+Qtz+Gln±Tlc in the eclogites. The M2 metamorphic stage consists of the assemblage Omp+Grt+Barr+Zo+Phe+Pg+Qtz and developed at 590–630°C and 14.5–16.5kbar suggesting a T increasing during decompression. After a further decompressional stage associated with a T decrease, the M3 tectono-metamorphic stage developed syn-kinematically with the main regional foliation S1. It is marked by the assemblage Phe+Pg+Grt+Chl+Ab/Olig+Hbl+Qtz+Rt/Ilm±Bt in metapelites and by Cam (blue-green)+Chl+Ab+Bt+Qtz+Rt in the re-equilibrated metabasite boudins. S1 developed during increasing T (from 550 to ca. 600°C) and sligthly increasing P (from 7 to 9kbar). Finally, the M4 assemblage grew as rims over the M3 minerals or overgrew the S1 regional foliation (albite porphyroblasts overgrowing the S1 foliation already defined by albite) and therefore can be considered as the final stage of the M3 stage. The P–T path proposed for the Monte Rosa nappe differs from previous works. In particular, we propose post-eclogitic decompression trajectory up to 7kbar, followed by a P–T increase that can be related to a second burial–exhumation cycle during Alpine orogenesis, as recently reported for other Alpine units.

Swept Blade Aerodynamics Numerical Simulation of Super-Critical HP Stage Static Cascade

Super-critical HP steam stage static blade cascade is as the prototype blade to numerical simulations. Different swept blades are made by changing the sweep angle and sweep height in order to study the effect of swept blade on aerodynamics characteristics of turbine static cascade. The numerical simulation sweep angle are made of ±10° and 0°,swept heights are 30% blade height. The turbine aerodynamics characteristics are analyzed by NUMECA software. The numerical simulation results indicate: that aft-sweep blades negative C-type pressure distribution increase the low energy fluid centralizing in end-wall corner and the end-wall secondary flow loss, but the loss is decreased at mid-span, depending on the baseline. But fore-sweep blades C-type pressure distribution decrease the low energy fluid centralizing in endwall corner and the endwall secondary flow loss, but the loss is increased at mid-span, depending on the baseline.

Combined Cycle Fatigue of Gas Turbine Blade Materials at Elevated Temperature

Abstract: In gas turbine engines for aerospace propulsion, and in particular in the HP and LP stage blading where the highest temperatures are experienced, the assessment of the fatigue damage mechanisms due to the interaction of high cycle fatigue (due to vibration phenomena) and low cycle fatigue (due to ground‐air‐ground major engine cycling) are of paramount importance for the structural integrity of the components. In order to experimentally evaluate the material performance in this highly demanding environment, a number of combined cycle fatigue (CCF) and low cycle fatigue (LCF) tests with and without dwell have been carried out on an investment cast polycrystalline nickel superalloy, at temperatures up to 870 °C, on specimens with pre‐cracked coating. Comparison of the CCF and the LCF tests with dwell with conventional LCF tests is presented herein.