Development of Cartridges for Aircraft Engine Cartridge Starters

1967 ◽  
Author(s):  
Joseph T. Hamrick
Keyword(s):  
High Pressure ◽  
Solid Propellant ◽  
Aircraft Engine ◽  
Experimental Investigations ◽  
Design Procedures ◽  
Hot Gas ◽  
Gas Source

The paper discusses the problems encountered in providing a high-pressure hot-gas source to the turbine of an aircraft engine starter, the methods of solving these problems, and the design procedures followed in arriving at a solid-propellant cartridge which functioned in all the environments encountered in both storage and operation. Development techniques and results of experimental investigations are presented.

scholarly journals Influence of material degradation on weld seam quality in hot gas butt welding of polyamides

2021 ◽  
Author(s):  
Max Bialaschik ◽  
Volker Schöppner ◽  
Mirko Albrecht ◽  
Michael Gehde
Keyword(s):  
Weld Seam ◽  
Experimental Investigations ◽  
Heating Process ◽  
Butt Welding ◽  
Hot Gas ◽  
Process Gas ◽  
Glass Fiber Reinforced ◽  
Extrusion Welding ◽  
Different Gases

AbstractThe joining of plastics is required because component geometries are severely restricted in conventional manufacturing processes such as injection molding or extrusion. In addition to established processes such as hot plate welding, infrared welding, or vibration welding, hot gas butt welding is becoming more and more important industrially due to its advantages. The main benefits are the contactless heating process, the suitability for glass fiber reinforced, and high-temperature plastics as well as complex component geometries. However, various degradation phenomena can occur during the heating process used for economic reasons, due to the presence of oxygen in the air and to the high gas temperatures. In addition, the current patent situation suggests that welding with an oxidizing gas is not permissible depending on the material. On the other hand, however, there is experience from extrusion welding, with which long-term resistant weld seams can be produced using air. Investigations have shown that the same weld seam properties can be achieved with polypropylene using either air or nitrogen as the process gas. Experimental investigations have now been carried out on the suitability of different gases with regard to the weld seam quality when welding polyamides, which are generally regarded as more prone to oxidation. The results show that weld strengths are higher when nitrogen is used as process gas. However, equal weld strengths can be achieved with air and nitrogen when the material contains heat stabilizers.

scholarly journals Particle Size Effects on Selectivity in Confined Bed Comminution

Minerals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 342
Author(s):  
Holger Lieberwirth ◽  
Lisa Kühnel
Keyword(s):  
Particle Size ◽  
High Pressure ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Size Effects ◽  
Experimental Investigations ◽  
Ore Processing ◽  
Tumbling Mills ◽  
Particle Bed ◽  
Vertical Roller

Confined bed comminution in high-pressure grinding rollers (HPGRs) and vertical roller mills (VRMs) was previously used preferably for grinding comparably homogeneous materials such as coal or clinker. Meanwhile, it started to complement or even replace tumbling mills in ore beneficiation with ore and gangue particles of rather different breakage behaviors. The selectivity in the comminution of a mixture of particles with different strengths but similar particle size distribution (PSD) of the constituents in a particle bed was investigated earlier. The strength of a material is, however, also a function of particle size. Finer particles tend to be more competent than coarser ones of the same material. In industrial ore processing using confined bed comminution, this effect cannot be neglected but even be exploited to increase efficiency. This paper presents research results on this topic based on experimental investigations with model materials and with natural particles, which were stressed in a piston–die press. It appeared that the comminution result substantially depends on the material characteristics, the composition of the mixture and the PSD of the constituents. Conclusions will be drawn for the future applications of selective comminution in mineral processing.

Evaluation of the Rotor Temperature Distribution of an Automotive Turbocharger Under Hot Gas Conditions Including Indirect Experimental Validation

2021 ◽  
Vol 143 (3) ◽  
Author(s):  
Christopher Zeh ◽  
Ole Willers ◽  
Thomas Hagemann ◽  
Hubert Schwarze ◽  
Jörg Seume
Keyword(s):  
Temperature Distribution ◽  
Heat Flow ◽  
Internal Combustion Engines ◽  
Fluid Film ◽  
Experimental Investigations ◽  
Inlet Temperature ◽  
Hot Gas ◽  
Experimental Identification ◽  
Fluid Film Bearings ◽  
Validation Parameters

Abstract While turbocharging is a key technology for improving the performance and efficiency of internal combustion engines, the operating behavior of the turbocharger is highly dependent on the rotor temperature distribution as it directly modifies viscosity and clearances of the fluid film bearings. Since a direct experimental identification of the rotor temperature of an automotive turbocharger is not feasible at an acceptable expense, a combination of numerical analysis and experimental identification is applied to investigate its temperature characteristic and level. On the one hand, a numerical conjugate heat transfer (CHT) model of the automotive turbocharger investigated is developed using a commercial CFD-tool and a bidirectional, thermal coupling of the CFD-model with thermohydrodynamic lubrication simulation codes is implemented. On the other hand, experimental investigations of the numerically modeled turbocharger are conducted on a hot gas turbocharger test rig for selected operating points. Here, rotor speeds range from 64.000 to 168.000 rpm. The turbine inlet temperature is set to 600 °C and the lubricant is supplied at a pressure of 300 kPa with 90 °C to ensure practically relevant boundary conditions. Comparisons of measured and numerically predicted local temperatures of the turbocharger components indicate a good agreement between the analyses. The calorimetrically determined frictional power loss of the bearings as well as the floating ring speed are used as additional validation parameters. Evaluation of heat flow of diabatic simulations indicates a high sensitivity of local temperatures to rotor speed and load. A cooling effect of the fluid film bearings is present. Consequently, results confirm the necessity of the diabatic approach to the heat flow analysis of turbocharger rotors.

Model of Effect of Hot Gas Ingress on Temperatures of Turbine Disks

2018 ◽  
Vol 141 (1) ◽  
Author(s):  
J. Michael Owen ◽  
Hui Tang ◽  
Gary D. Lock
Keyword(s):  
Boundary Layer ◽  
High Pressure ◽  
Flow Rate ◽  
Frictional Heating ◽  
Practical Importance ◽  
Combined Effects ◽  
Buffer Effect ◽  
Cooling Flow ◽  
Hot Gas ◽  
Radial Outflow

Ingress is the leakage of hot mainstream gas through the rim-seal clearance into the wheel-space between the rotating turbine disk (the rotor) and the adjacent stationary casing (the stator). The high-pressure rotor is purged by a radial outflow of air from the high-pressure compressor, and this cooling air is also used to reduce the ingress. The engine designer needs to predict the stator and rotor temperatures as a function of cooling-flow rate. The sealing effectiveness determines how much air is needed to reduce or prevent ingress; although there are numerous theoretical and experimental papers on the effectiveness of different seal geometries, there are few papers on the effect of ingress on the temperature of the rotating disk. This is an unsolved problem of great practical importance: under high stress, a small increase in metal temperature can significantly reduce operating life. In this paper, conservation equations and control volumes are used to develop theoretical equations for the exchange of mass, concentration and enthalpy in an adiabatic rotor–stator system when ingress occurs. It is assumed that there are boundary layers on the rotor and stator, separated by an inviscid rotating core, and the fluid entrained from the core into the boundary layer on the rotor is recirculated into that on the stator. The superposed cooling flow protects the rotor surface from the adverse effects of hot-gas ingress, which increases the temperature of the fluid entrained into the rotor boundary layer. A theoretical model has been developed to predict the relationship between the sealing effectiveness on the stator and the adiabatic effectiveness on the rotor, including the effects of both ingress and frictional heating. The model involves the use of a nondimensional buffer parameter, Ψ, which is related to the relative amount of fluid entrained into the rotor boundary layer. The analysis shows that the cooling flow acts as a buffer, which attenuates the effect of hot gas ingress on the rotor, but frictional heating reduces the buffer effect. The theoretical effectiveness curves are in good agreement with experimental data obtained from a rotor–stator heat-transfer rig, and the results confirm that the buffer effect increases as the sealing effectiveness of the rim seals decreases. The analysis quantifies the increase in the adiabatic rotor temperature due to direct frictional heating, which is separate from the increase due to the combined effects of the ingress and the indirect frictional heating of the entrained fluid. These combined effects are reduced as Ψ increases, and Ψ = 1 at a critical flow rate above which there is no entrained fluid and consequently no indirect heating of the rotor. The model also challenges the conventional physical interpretation of ingress as, in general, not all the hot gas that enters the rim-seal clearance can penetrate into the wheel-space. The ingress manifests itself through a mixing of enthalpy, which can be exchanged even if no ingested fluid enters the wheel-space.

Innovative Minimally Intrusive Sensor Technology Development for Versatile Affordable Advanced Turbine Engine Combustors

2002 ◽  
Author(s):  
Neil Goldstein ◽  
Carlos A. Arana ◽  
Fritz Bien ◽  
Jamine Lee ◽  
John Gruninger ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Real Time ◽  
Gas Turbines ◽  
High Performance ◽  
Chemical Species ◽  
Sensor Technology ◽  
Spectral Signature ◽  
Temperature Pattern ◽  
Hot Gas

The feasibility of an innovative minimally intrusive sensor for monitoring the hot gas stream at the turbine inlet in high performance aircraft gas turbine engines was demonstrated. The sensor uses passive fiber-optical probes and a remote readout device to collect and analyze the spatially resolved spectral signature of the hot gas in the combustor/turbine flowpaths. Advanced information processing techniques are used to extract the average temperature, temperature pattern factor, and chemical composition on a sub-second time scale. Temperatures and flame composition were measured in a variety of combustion systems including a high pressure, high temperature combustion cell. Algorithms for real-time temperature measurements were developed and demonstrated. This approach should provide a real-time temperature profile, temperature pattern factor, and chemical species sensing capability for multi-point monitoring of high temperature and high pressure flow at the combustor exit with application as an engine development diagnostic tool, and ultimately, as a real-time active control component for high performance gas turbines.

Evaluation of the Rotor Temperature Distribution of an Automotive Turbocharger Under Hot Gas Conditions Including Indirect Experimental Validation

2020 ◽  
Author(s):  
Christopher Zeh ◽  
Ole Willers ◽  
Thomas Hagemann ◽  
Hubert Schwarze ◽  
Joerg R. Seume
Keyword(s):  
Temperature Distribution ◽  
Heat Flow ◽  
Internal Combustion Engines ◽  
Fluid Film ◽  
Experimental Investigations ◽  
Inlet Temperature ◽  
Hot Gas ◽  
Experimental Identification ◽  
Fluid Film Bearings ◽  
Validation Parameters

Abstract While turbocharging is a key technology for improving the performance and efficiency of internal combustion engines, the operating behavior of the turbocharger is highly dependent on the rotor temperature distribution as it directly modifies viscosity and clearances of the fluid film bearings. Since a direct experimental identification of the rotor temperature of an automotive turbocharger is not feasible at an acceptable expense, a combination of numerical analysis and experimental identification is applied to investigate its temperature characteristic and level. On the one hand, a numerical conjugate heat transfer (CHT) model of the automotive turbocharger investigated is developed using a commercial CFD-tool and a bidirectional, thermal coupling of the CFD-model with thermohydrodynamic lubrication simulation codes is implemented. On the other hand, experimental investigations of the numerically modelled turbocharger are conducted on a hot gas turbocharger test rig for selected operating points. Here, rotor speeds range from 64.000 to 168.000 rpm. The turbine inlet temperature is set to 600°C and the lubricant is supplied at a pressure of 300 kPa with 90°C to ensure practically relevant boundary conditions. Comparisons of measured and numerically predicted local temperatures of the turbocharger components indicate a good agreement between the analyses. The calorimetrically determined frictional power loss of the bearings as well as the floating ring speed are used as additional validation parameters. Evaluation of heat flow of diabatic simulations indicates a high sensitivity of local temperatures to rotor speed and load. A cooling effect of the fluid film bearings is present. Consequently, results confirm the necessity of the diabatic approach to the heat flow analysis of turbocharger rotors.

Experimental Investigations on High Pressure Gasoline Injection up to 800 bar for Different Combustion Modes

MTZ worldwide ◽  
2019 ◽  
Vol 80 (3) ◽  
pp. 52-57 ◽  
Author(s):  
Andreas Stadler ◽  
Reinhardt Brunner ◽  
Georg Wachtmeister ◽  
Henning Sauerland
Keyword(s):  
High Pressure ◽  
Experimental Investigations ◽  
Combustion Modes

Dynamic response of bridges under travelling loads

1993 ◽  
Vol 20 (2) ◽  
pp. 287-298 ◽  
Author(s):  
J. L. Humar ◽  
A. M. Kashif
Keyword(s):  
Dynamic Response ◽  
Rational Design ◽  
Weight Ratio ◽  
Experimental Investigations ◽  
Speed Ratio ◽  
Force Model ◽  
Beam Model ◽  
Dynamic Amplification Factor ◽  
Design Procedures ◽  
Dynamic Amplification

In spite of a number of analytical and experimental investigations on the dynamic response of bridges to moving vehicle loads, the controlling parameters that govern the response have not been clearly identified. This has, in turn, inhibited the development of rational design procedures. Based on an analytical investigation of the response of a simplified beam model traversed by a moving mass, the present study identifies the governing parameters. The results clearly show why attempts to correlate the response to a single parameter, either the span length or the fundamental frequency, are unsuccessful. Simple design procedures are developed based on relationships between the speed ratio, the weight ratio, and the dynamic amplification factors; and a set of design curves are provided. Key words: dynamic response of bridges, vehicle–bridge interaction, moving force model, moving sprung mass model, dynamic amplification factor.

On Thermoeconomics of a Sensible Heat, Thermal Energy Storage System

1995 ◽  
Vol 117 (3) ◽  
pp. 255-259 ◽  
Author(s):  
M. A. Badar ◽  
S. M. Zubair
Keyword(s):  
Heat Storage ◽  
Storage System ◽  
Energy Storage System ◽  
Optimum Number ◽  
Sensible Heat ◽  
Hot Gas ◽  
Gas Source ◽  
Charging Time ◽  
Thermal Energy Storage System ◽  
Form Model

A closed-form model for the second-law-based thermoeconomic optimization of a sensible heat storage system, in which the energy is stored in a large liquid bath from a hot-gas source, is discussed with an example problem. The results are compared with those obtained from Bejan’s analysis to illustrate usefulness of the present approach. The influence of important parameters on the optimum number of heat transfer units Ntu,opt, and dimensionless charging time θopt, are presented in a graphic form.

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