Burst Disk Research Articles

Dynamic Mechanisms of High-Pressure Hydrogen Self-Ignition and Flame Evolution in Obstructed Tubes: Experimental Insights and Implications

Experimental investigations on high-pressure hydrogen release into obstructed tubes with varying obstacle positions are conducted to explore the dynamic mechanisms of shock propagation, self-ignition and flame evolution. High-speed photography, pressure sensor and light detector are used in the experiments. The results reveal that obstacle position significantly affects self-ignition by the multi-dimensional interactions and the turbulence-promoted mixing. The reflected shock results in an overpressure rise of twice that behind the leading shock. In addition, the intensity of reflected shock decreases when it propagates upstream. The critical burst pressure for self-ignition first decreases and then increases with a further obstacle position away from the burst disk. The lowest burst pressure for self-ignition is 2.08 MPa arising in the tube with obstacles located at 200 mm axially, half that of the smooth tube. In obstructed tubes, three possible self-ignition regions exist, including inclined obstacle walls, tube centerline and tube sidewalls. The patterns of self-ignition are determined by burst pressure and obstacle position. Besides, flame acceleration is observed in the obstructed, which is related to turbulence promoted by the shock-obstacle interaction. The farther obstacles from the burst disk results in more marked effects on flame acceleration.

Effects of internal intervention in tubes on shock wave attenuation, formation and propagation of flame during high-pressure hydrogen release

Experiments on the impacts of the combination of fin structure and expansion chamber on shock wave attenuation, hydrogen ignition, and flame characteristics during high-pressure hydrogen release were carried out. The fin is a four-edged platform hollowed out on all sides. The inflated upper and lower tube walls are located 85, 95, and 105 mm away from the nickel burst disk. With the incident shock wave traveling through the fin, the reflected shock and the superposition of multiple reflected shock waves appear, and the reflected shock wave intensity can equal that of the release pressure. The decrease of the incident shock wave intensity behind the fin leads to the decrease of the non-uniformity of the mixed layer temperature, further causing the decrease of the flame propagation velocity. The presence of fins increases the probability of ignition in the fin region and the critical release pressure for ignition is significantly lower than that in the barrier free tube, mainly because the fin inside intensifies the hydrogen/air mixture, resulting in a lower minimum ignition energy required for self-ignition. Furthermore, the decrease of flame propagation velocity leads to the increase of hydrogen consumption inside the tube and the decrease of shock overpressure outside.

Experimental Investigation into Shockwave and Flame Characteristics of Hydrogen Released through Various Pressure Relief Devices

This paper presents an experimental investigation into shockwave and flame characteristics of compressed hydrogen released through various types of pressure relief devices (PRDs) for which data have not been previously reported. Burst disks and safety valves with different set pressure (P0) of 22–140 MPa were tested. Shockwave intensity/velocity spontaneous ignition/flame behavior was monitored by in-situ pressure/light sensors, respectively. Previous works have mostly focused on burst disks with low P0 (under 10 MPa), leaving safety valves and high-pressure burst disks uninvestigated. It was found that shockwave/spontaneous ignition behavior differs with PRD types. Spontaneous ignition occurs in all burst disk cases, along with an ignition/self-extinguishment/reignition process with relatively low P0, which has not been revealed previously. In contrast, none of the safety valves cause spontaneous ignition, resulting from the absence of shockwave due to lower overpressure values/rise rate during release. This suggests that shockwave formed by sudden release is the most dominant factor in spontaneous ignition. Also, the occurrence of self-extinguishment does not guarantee the absence of jet flame. This work provides a comprehensive database revealing shockwave and flame characteristics of hydrogen released through different PRDs, which offers basic data and theoretical support for the safety and risk assessment of high-pressure hydrogen facilities.

Spallation Neutron Source Hydrogen Relief Analysis for the Cryogenic Moderator System

The Spallation Neutron Source at Oak Ridge National Laboratory operates the Cryogenic Moderator System (CMS) which provides hydrogen cooling at 20K to three neutron moderators. Each hydrogen loop is protected by multiple burst discs and reclosing relief valves. As a result of the Proton Power Upgrade project, the CMS moderator loops will hold more hydrogen and thus require piping modifications. Operational experience has demonstrated that transient pressure increases in these hydrogen loops occasionally result in the rupture of the burst discs. The causes for pressure transients in the system that might lead to hydrogen venting are varied and complex, for example loss of vacuum or cooling. Dynamic simulation and analysis of the parameters considered as the worst-case relief venting scenario were performed and will be presented.

Numerical study on the effects of the obstacle shapes on the spontaneous ignition of high-pressure hydrogen in a tube

It is necessary to investigate the impact of different obstacle shapes on high-pressure hydrogen spontaneous ignition due to the role obstacles play in promoting its generation. This paper first carried out model validation and found that the simulation could accurately reproduce the position and time of the initial flame detection, flame evolution, and pressure in the triangular-shaped obstacle tube as observed in the experiments. Subsequently, simulations were employed to explore the impact of three different obstacle shapes (triangular-shaped, arc-shaped, and square-shaped) on spontaneous ignition with the tube. The variation in obstacle shapes affects the initial flame detection position and the length of the flame, while it has minimal impact on the spontaneous ignition time. The square-shaped obstacles result in the closest initial flame detection position point to the burst disk and the longest flame in the tube, followed by the arc-shaped obstacles, and finally the triangular-shaped obstacles.

Primary osteoarthritis of the lumbar spine presenting as chronic low back pain or sciatica or both (prolapsed lumber disc syndrome): establishing its cause, pathogenesis, and treatment: A randomized case-control study

: The objectives of this study were to compare three scores, Western Ontario McMaster Universities Osteoarthritis Index (WOMAC), Oswestry Disability Index (ODI) for low back pain, and Visual Analogue Scale (VAS) Vertical Version at the beginning and end point in two, Trial (G1), and Control (G2) groups of Primary Osteoarthritis of lumbar spine patients.The inner nucleus pulposus may rupture out from the annulus as the disc continues to degrade or as the spine continues to be stressed. This is a herniated or burst disc. The nerve roots that are immediately behind the disc space may then be pressed by the disc material fragments. This may result in discomfort, frailty, numbness, or alterations in feeling.: Understanding the causes, pathophysiology, and treatments for prolapsed lumber disc syndrome, which presents as primary osteoarthritis of the lumbar spine and causes chronic low back pain, sciatica, or both.: In this study, the total number of patients were 150, in G1 - 100, and G2 - 50. G1 received the hypothesized treatment, Contracture Correction Therapy (CCT), while G2 did “No Therapy”. WOMAC determination was done by the questionnaire; ODI by modified Oswestry Low Back pain disability questionnaire and VAS by Visual Analogue Scale Vertical Version, all at 0, 6, 12, and 24 weeks. The CCT consisted of 1. Immobilization of the spine. 2. Passive and active extension of the spine. 3. Three therapeutic rituals and 4. Advice to avoid stooping.: The CCT receiving was associated with much recovery (P <0.00) while non-receiving with much less (P =0.00). In G1 WOMAC decreased from 54.29 to 0.00; ODI from 51.82 to 1.80; VAS rose from 37.56 to 100 (rise indicates betterment) P= 0.00. In G2 WOMAC lowered from 56.40 to 4.08; ODI from 65.10 to 6.0; VAS rose from 34.40 to 81.00. Relief in symptoms was similar.: The cause, pathogenesis, and treatment are deficient full extension, I.V. joint capsule contracture formation, and extension of the lumbar spine respectively.

Thermal runaway-induced current interrupt device and vent activation behaviour in an 18650 lithium-ion battery cap using the Johnson-Cook criterion

Lithium-ion batteries (LIBs) thermal safety issues such as thermal runaway (TR) triggered by thermal or mechanical abuse have been one of the most important factors hindering its development at present. In order to effectively release the excessive pressure caused by TR, a safety vent is used as a reliable safety device in commercial LIBs. However, the current interrupt device (CID) and vent activation behaviour and mechanism are still unclear in the mesoscale. Herein, finite element simulations of metallic material deformation and failure during CID and vent activation at preset dynamic incremental pressure loads and various constant temperatures for a commercial 18650 LIB were carried out by introducing the Johnson-Cook (J-C) damage model in this study. The three-dimensional evolution, dynamical and mechanical analysis of the deformation to damage behaviour are quantitatively characterized. The CID- and vent-activation pressure based on the J-C damage criterion is significantly higher than the pressure value corresponding to the maximum von Mises stress. The results show fracture strain of the burst disk notch and plate will not exceed 0.93 % and 0.048 % respectively when the TR reaches the onset temperature. The temperature-dependent activation time reduction rate was developed to quantify the effect of temperature on the CID-and vent-activation times, indicating that TR temperature's effect on vent activation is significantly stronger than that of CID. These results may provide a reliable guide to LIB safety design.

Effect of Al-made burst disk on the shock wave and the spontaneous ignition of high-pressure hydrogen during its sudden discharge

Hydrogen is regarded as the promising energy carrier in the next decades. However, the spontaneous ignition of pressurized hydrogen is one of the safety hazards blocking its safe utilization. In this paper, effect of the Al-made burst disk on the shock wave and the spontaneous ignition of high-pressure hydrogen is experimentally studied and discussed in detail through comparison with the previous results when Ni was used as a material. Pressure transducers and light sensors are employed to detect the shock wave and spontaneous ignition respectively. It is found that shock intensity, i.e., shock pressure and shock speed, decreases with the use of Al. As a result, the minimum burst pressure increases from 4.09 MPa for Ni to 4.51 MPa for Al. The result of the estimation of burst disk opening time and pressure profiles inside high-pressure storage tank prove that the opening time of Al is longer than Ni, which causes the wider hydrogen/air mixture area. The distance L between the contact surface and the leading shock wave increases with the increasing of Mach number, results in the short distance between contact surface and the leading shock wave for Al. After the mixing of cold hydrogen and heated air with high temperature that is close to the leading shock wave, spontaneous ignition occurs early inside the Al-made tubes.

Thermonuclear type-I X-ray bursts and burst oscillations from the eclipsing AMXP swift J1749.4–2807

ABSTRACT Swift J1749.4-2807 is the only known eclipsing accreting millisecond X-ray pulsar. In this paper, we report on seven thermonuclear (Type-I) X-ray bursts observed by NICER during its 2021 outburst. The first six bursts show slow rises and long decays, indicative of mixed H/He fuel, whereas the last burst shows fast rise and decay, suggesting He-rich fuel. Time-resolved spectroscopy of the bursts revealed typical phenomenology (i.e. an increase in blackbody temperature during the burst rise, and steady decrease in the decay), however, they required a variable NH. We found that the values of NH during the bursts were roughly double those found in the fits of the persistent emission prior to each burst. We interpret this change in absorption as evidence of burst–disc interaction, which we observe due to the high inclination of the system. We searched for burst oscillations during each burst and detected a signal in the first burst at the known spin frequency of the neutron star (517.92 Hz). This is the first time burst oscillations have been detected from Swift J1749.4-2807. We further find that each X-ray burst occurs on top of an elevated persistent count rate. We performed time-resolved spectroscopy on the combined data of the bursts with sufficient statistics (i.e. the clearest examples of this phenomenon) and found that the blackbody parameters evolve to hotter temperatures closer to the onset of the bursts. We interpret this as a consequence of an unusual marginally stable burning process similar to that seen through mHz QPOs.

Numerical study on the influence mechanism of different types of burst disc on high pressure hydrogen spontaneous combustion in tube

High-pressure transportation and storage are the current main methods for storing hydrogen. Burst discs, which are common in high-pressure storage devices, can cause hydrogen leaks to ignite and create serious accidents when certain conditions are met. To investigate this, this paper studies the effect of different blasting slot shapes on the spontaneous combustion of leaked high-pressure hydrogen. Numerical simulations, using LES, EDC model, Ten-Step Burst Disc Opening Method and 19-Step Detailed Hydrogen Combustion Mechanism, were conducted to analyze the spontaneous combustion of hydrogen with annular grooves, star grooves, cross grooves and grooveless burst discs. The results of the study show that the shape of the groove in the bursting disc will significantly affect the shock wave structure and spontaneous combustion time of leaked high pressure hydrogen in the tube. Among the four types of bursting discs, the order of spontaneous combustion in the tube is annular groove (approximately 90 μs), star groove (approximately 110 μs), cross groove (approximately 120 μs), and grooveless bursting disc (approximately 130 μs). Secondly, the double spherical shock waves produced by annular groove bursting disc collide with each other, resulting in a higher rising speed of pressure and temperature in the tube than with other bursting discs. Finally, the spontaneous combustion time of the leaked hydrogen is proportional to the open area of the bursting disc. When the opening area is the same, the smaller the exit shape coefficient is, the shorter the spontaneous combustion time is. The research results can provide some reference for the design and application of bursting disc in high pressure hydrogen storage equipment.

3D Transient CFD Simulation of an In-Vessel Loss-of-Coolant Accident in the EU DEMO WCLL Breeding Blanket

The in-vessel Loss-of-Coolant Accident (LOCA) is one of the design basis accidents in the design of the EU DEMO tokamak fusion reactor. System-level codes are typically employed to analyse the evolution of these transients. However, being based on a lumped approach, they are unable to quantify localised quantities of interest, such as local pressure peaks on the vacuum vessel walls, to which the failure criteria are linked. To calculate local quantities, the 3D nature of the phenomenon needs to be considered. In this work, a 3D transient model of the in-vessel LOCA from a water-cooled blanket is developed. The model is implemented in the commercial CFD software STAR-CCM+. It simulates the propagation of the water jet in the vessel from the beginning of the accident, thus accounting for the phase change of the water, i.e., from the pressurised liquid phase to the vapour phase inside the vessel, being the latter at a much lower pressure than in the blanket coolant pipes. Due to the large pressure ratio (>1000), shocks are expected; therefore, an Adaptive Mesh Refinement (AMR) algorithm is employed. The physical models (in particular, the multiphase model) are benchmarked to a 2D reference problem before being applied to the 3D EU DEMO-relevant problem. The simulation results show that the pressure peaks in front of the vessel walls are not dangerous as they are below the design limit. The entire evolution of the water jet is followed up to the opening of the burst disks, in order to compare the average pressure evolution with that computed with system-level codes. A comparison with the in-vessel LOCA from a helium-cooled blanket is also carried out, showing that the accident evolution in the water case is less violent than in the helium case.

Numerical investigation on the shock wave propagation, hydrogen/air mixing and spontaneous ignition induced by high-pressure hydrogen release inside the tubes with different shaped cross-sections

Hydrogen is regard as one of the most promising primary energy vectors solving the problems of air pollution and energy shortage. However, the spontaneous ignition is a major hazard during the application of high-pressure hydrogen. In this paper, a numerical investigation is conducted to study the shock wave propagation, hydrogen/air mixing and spontaneous ignition induced by high-pressure hydrogen release into the tubes with square, pentagon and circular cross-sections (tube wall angles are 90, 108 and 180° respectively). Large Eddy Simulation, Eddy Dissipation Concept coupling with the detailed hydrogen/air reaction mechanism and 10-step like opening process of burst disk are employed. The numerical results of ignition conditions and positions agree well against the previous experimental results. In the square and pentagon tubes, the inward-reflected and outward-reflected shock wave could be generated simultaneously and interact with each other due to the radial propagation of leading shock wave. In the circular tube, however, the two types of reflected shock generate alternately and the interaction disappears. The higher viscous resistance at wall corner induces the formation of velocity shear layer on the tube wall, which promotes the mixing of hydrogen and air. The increase of the angle of wall corner reduces the flammable mixture with the chemical equilibrium equivalence ratio on the tube wall due to the low viscous resistance and short velocity shear layer. The ignition delay time/distance and combustion intensity decrease with the increase of the angle of wall corner. After the occurrence of spontaneous ignitions in the non-circular tubes, the flame propagates downstream and its length increases rapidly along the wall corner. In addition, larger combustion area could be observed with the decrease of the angle of wall corner.

Analyses of Critical Hydrogen Enrichment in PWR Containment Compartments

During a loss-of-coolant accident in a pressurized water reactor (PWR), steam of varying quality is released from the primary circuit into the equipment compartments of the containment, followed by the release of a hydrogen-steam mixture during the core degradation phase. In the case of long-lasting accidents, findings of detailed code analyses indicate an enrichment of hydrogen in lower peripheral containment compartments in the reference PWR plant under investigation. During the late accident phase with ex-vessel molten core–concrete interaction, even in the case of an operating passive autocatalytic recombiner system, this poses a threat for local hydrogen combustion later on. Such hydrogen phenomena are not expected and have not been widely studied up to now. Therefore, corresponding experiments have been performed at the THAI test facility operated by Becker Technologies. One of these tests had been precalculated with the COntainment COde SYStem (COCOSYS) as part of the Gesellschaft für Anlagen- und Reaktorsicherheit (GRS) code system AC2 and has been used to validate the code. The 60-m3 THAI test vessel has been divided into an inner compartment that has been connected to the surrounding vessel, simulating the upper and peripheral containment part, by very small flow openings at the bottom representing the clearance between door frames and door leaves and one opening at the top representing typical openings by burst disks. The paper discusses both the experimental findings of a test series on the potential enrichment of hydrogen in lower containment compartments and the COCOSYS calculations demonstrating the applicability of the code under complex flow conditions including stratification phenomena.

Effects of obstacles inside the tube on initial self-ignition of high-pressure hydrogen release through a tube

The safe application of hydrogen has attracted increased attention. In particular, fire and explosion disasters may be induced by self-ignition during high-pressure hydrogen leakage. This study experimentally investigates the effect of obstacles on initial self-ignition when high-pressure hydrogen is suddenly released. High-pressure hydrogen release experiments are performed at burst pressures of 2–8 MPa. The hydrogen flame inside the tube is captured by a high-speed video camera and light sensors, and shock wave variations are measured by pressure transducers. The results show that the presence of obstacles inside the tube significantly affects shock wave flow. It is found in this study that obstacles decrease the minimum burst pressure needed for self-ignition and self-ignition is prone to occur in the vicinity of obstacles. The influence of obstacles on the initial ignition process are different at different self-ignition locations. On the one hand, the reflected shock wave originating from obstacles is the main reason for the promotion of self-ignition upstream of obstacles. On the other hand, the formation of a hydrogen/air mixture under the effect of turbulent flow and multi-dimensional shock waves leads to self-ignition downstream of obstacles. Meanwhile, the presence of obstacles before the initial ignition location (Lin) shortens the distance between the ignition location and the burst disk and significantly accelerates the occurrence of initial self-ignition. Obstacles participate in the self-ignition process earlier when they are placed closer to the burst disk. However, obstacles after the initial ignition location (Lin) show no effect on the initial ignition process. The results can guide the safe use of high-pressure hydrogen.

Burst speed prediction and reliability assessment of turbine disks: Experiments and probabilistic aspects

Under harsh and stochastic environmental conditions, turbine disks may exceed their maximum allowable speed and then burst. Aeroengine certification requires demonstrating its integrity at higher rotation speeds than the designed steady-state speed. In particular, testing the burst speed of turbine disk is an essential part of this procedure. In this work, based on the average stress approach, a novel model for turbine disk burst speed assessment is proposed, in which the notch strength ratio and the stress triaxiality parameter are introduced to characterize the inhomogeneous stress field and multiaxial stress state, respectively. Disk overspeed test data are utilized for model validation and comparison, and results show that the proposed model matches the experimental evidences well. Furthermore, a probabilistic framework is built to characterize the influence of material property dispersion on burst speed, and the proposed model is extended to a probabilistic one. Finally, the relationship between the safety margin and the reliability index is established, which provides a reference for reliability-based design and evaluation of turbine disk.

Numerical study on the shock evolution and the spontaneous ignition of high-pressure hydrogen during its sudden release into the tubes with different angles

High-pressure hydrogen storage is one of the best choices of hydrogen storage at present and in the future. However, the spontaneous ignition of high-pressure hydrogen release blocks its wide application. This paper further studies the shock evolution, temperature accumulation and spontaneous ignition inside the tubes with different angles by employing LES, RNG and EDC models, 10-step like opening process of burst disk and detailed hydrogen/air combustion mechanism. Four tubes with different angles (60, 90, 120 and 150°) are employed based on the previous experimental result. It is found that the smaller the angle of the tube, the greater the maximum pressure and temperature of the first shock reflection zone. And the maximum pressure and temperature of the second shock reflection zone is the highest inside the 90° angle tube. This is due to two shock reflection mechanisms inside the tubes: in acute angle tube, only the reflected hemispherical shock hits the inner wall of the tube corner, however, for non-acute tubes, both the reflected hemispherical shock and reflected normal shock hit the inner wall of the tube corner. In addition, it requires a longer time and a further distance to initiate the spontaneous ignition inside the tubes with larger angle. And the flame induced by the spontaneous ignition could move upstream steadily inside the 60° angle tube and the flame length increases with the release time to a maximum value of 21.44 mm.

Numerical simulation of the effect of multiple obstacles inside the tube on the spontaneous ignition of high-pressure hydrogen release

Self-ignition may occur during hydrogen storage and transportation if high-pressure hydrogen is suddenly released into the downstream pipelines, and the presence of obstacles inside the pipeline may affect the ignition mechanism of high-pressure hydrogen. In this work, the effects of multiple obstacles inside the tube on the shock wave propagation and self-ignition during high-pressure hydrogen release are investigated by numerical simulation. The RNG k-ε turbulence model, EDC combustion model, and 19-step detailed hydrogen combustion mechanism are employed. After verifying the reliability of the model with experimental data, the self-ignition process of high-pressure hydrogen release into tubes with obstacles with different locations, spacings, shapes, and blockage ratios is numerically investigated. The results show that obstacles with different locations, spacings, shapes and blockage ratios will generate reflected shock waves with different sizes and propagation trends. The closer the location of obstacles to the burst disk, the smaller the spacing, and the larger the blockage ratio will cause the greater the pressure of the reflected shock wave it produces. Compared with the tubes with rectangular-shaped, semi-circular-shaped and triangular-shaped obstacles, self-ignition is preferred to occur in tube with triangular-shaped obstacles.

Spontaneous Ignition of Cryo-Compressed Hydrogen in a T-Shaped Channel System

Sudden releases of pressurised hydrogen may spontaneously ignite by the so-called “diffusion ignition” mechanism. Several experimental and numerical studies have been performed on spontaneous ignition for compressed hydrogen at ambient temperature. However, there is no knowledge of the phenomenon for compressed hydrogen at cryogenic temperatures. The study aims to close this knowledge gap by performing numerical experiments using a computational fluid dynamics model, validated previously against experiments at atmospheric temperatures, to assess the effect of temperature decrease from ambient 300 K to cryogenic 80 K. The ignition dynamics is analysed for a T-shaped channel system. The cryo-compressed hydrogen is initially separated from the air in the T-shaped channel system by a burst disk (diaphragm). The inertia of the burst disk is accounted for in the simulations. The numerical experiments were carried out to determine the hydrogen storage pressure limit leading to spontaneous ignition in the configuration under investigation. It is found that the pressure limit for spontaneous ignition of the cryo-compressed hydrogen at temperature 80 K is 9.4 MPa. This is more than 3 times larger than pressure limit for spontaneous ignition of 2.9 MPa in the same setup at ambient temperature of 300 K.

Burst–Disk Interaction in 4U 1636–536 as Observed by NICER

We present the detection of 51 thermonuclear X-ray bursts observed from 4U 1636–536 by the Neutron Star Interior Composition Explorer (NICER) over the course of a 3 yr monitoring campaign. We perform time-resolved spectroscopy for 40 of these bursts and show the existence of a strong soft excess in all the burst spectra. The excess emission can be characterized by the use of a scaling factor (the f a method) to the persistent emission of the source, which is attributed to the increased mass accretion rate onto the neutron star due to Poynting–Robertson drag. The soft excess emission can also be characterized by the use of a model taking into account the reflection of the burst emission off the accretion disk. We also present time-resolved spectral analysis of five X-ray bursts simultaneously observed by NICER and AstroSat, which confirm the main results with even greater precision. Finally, we present evidence for Compton cooling using seven X-ray bursts observed contemporaneously with NuSTAR, by means of a correlated decrease in the hard X-ray lightcurve of 4U 1636–536 as the bursts start.

A design approach for controlled blade-off in overspeeding turbines

Following a shaft failure or loss of load in a gas turbine engine, the turbine overspeeds due to the continuing expansion through the stage(s). The overspeed may result in hazardous conditions which have to be prevented. Several mitigation methods include the control system’s response by shutting the fuel flow, mechanical friction to reduce turbine acceleration, and blade release at a predetermined rotational speed. The release of the blades not only terminates the gas torque which accelerates the disk, but also increases the disk burst speed at reduced centrifugal load. In this manuscript, a design space exploration is presented to avoid disk burst by blade-off in a civil large turbofan engine through a parametric design of blade firtree and disk post system. The firtree design parameters used in the study are the contact angle between the blade firtree and the disk post, firtree bottom flank angle, firtree flank length and firtree thickness with respect to the disk post. The LS-DYNA finite element software was used in the simulations to generate possible failure scenarios. These were ‘disk burst’ and ‘blade-off’. Blade-off conditions manifested in two ways as a function of design parameters. The first type was blade release from serrations without disk post failure, and the second type was blade escape with disk post failure. Following the design space exploration, the effect of several design and material parameters on the design space was investigated. These parameters are; the contact friction coefficient between the blade firtree and disk post, firtree serration number, and the strain hardening behavior of the material.