Combined Experimental/Finite Element Investigation of Transverse Barrel Movement

Transverse barrel movement was measured during the firing of a Ruger Precision Rifle chambered in 6.5 Creedmoor. The use of laser vibrometers enabled high speed measurement at good resolution during the projectile in-bore transient. Lateral vibrations have been broken into constituents based on source using a combination of experiments and finite element modeling. Individual contributors to overall vibration discussed include firing pin impact, primer ignition, and the combined load of combustion gas pressure and projectile-bore interaction. Good correlation was obtained between barrel motion in the vertical plane and model predictions during the in-bore period. It was concluded that action of the firing pin and primer impulse contribute significantly to the overall dynamic response of the barrel.

Numerical Simulation of the Effects of Oil Gun Location and Oil Feed Rate on Coal Ignition and Burner Wall Temperature in a Tiny Oil Ignition Burner

To solve the overheating problem of tiny oil ignition burners’ walls during the firing-up process in a 330 MWe tangentially pulverized coal-fired boiler, a numerical model of a tiny oil ignition burner was carefully built considering combustion, gas–solid flow, and heat transfer. Then, the burner location and oil feed rate were optimized based on the model to prevent the burner’s walls from overheating. The effects of the oil gun extension distance (100, 200, 300, 400, 500 mm) and oil feed rate (160, 140, 120, 100, 80, 70, 60 kg/h) on coal ignition performance and burner wall temperature were carefully investigated. The simulation results showed good agreement with the measured results. The results indicated that decreasing the oil gun distance within the burner diminished the flame length of the co-combustion of oil and pulverized coal, thus lowering the burner wall temperature. Decreasing the oil feed rate appropriately could also reduce the burner wall temperature without influencing the ignition performance. Considering both ignition performance and burner wall temperature, an extension of 400 mm of the oil gun location and an oil feed rate of 160 kg/h were successfully applied to the actual operation without adverse effects. Moreover, it is suggested to move the temperature monitor points from the burner upper wall to the burner side wall.

Design, Structural and Thermal Analysis of Piston by Using Finite Element Analysis

In this project, it was chosen to investigate a specific piston design and its maximum gas pressure capabilities. The first aim for this project is to create a piston model using the solid modelling software CATIA V5. The geometry will be meshed and analyzed using the ANSYS software. A thorough literature search was conducted for the examination of piston input circumstances and the analytical process. High combustion gas pressures operate as mechanical loads, causing substantial strains in the piston's critical area. For various loading situations, such as maximum gas pressure load, a detailed static structural analysis is carried out. To choose the best material, a comparative research is carried out. Relative examination is never really dominated material. A cylinder is a mechanical part found in an assortment of cycles like pneumatic chambers. Responding siphons, responding motors and gas blowers. It is the upward development inside a chamber that is put away gastight by cylinder .In the auto business, it is found that the cylinder is the most fundamental part of the motor, and that it is presented to serious mechanical and warm loads. Warm burdens are initiated in the cylinder because of the exceptionally high temperature differential between the cylinder crown and the cooling displays. The cylinders are regularly built of aluminum due to its lightweight and heat conductivity. Be that as it may, as a result of its low hot strength and high development coefficient, it isn't suggested for use in high-temperature applications. The reason for a section bar or potentially an associating bar in a motor is to move power from growing gas to the barrel shaped shaft through an interfacing bar and additionally segment pole. To pack or remove the liquid put away in the chamber, the siphons turned around the capacity of the cylinder and communicate power from driving rod to it. In the initial step the primary examination of a common cylinder developed of the aluminum composite is concentrated in this exploration. The subsequent advance is to direct an investigation on a cylinder developed of Aluminum and Cast iron. Lightweight, minimal expense, primarily and thermally safe materials ought to be used in the development of pistons in the third step Validation of investigation result with contrasting the traditional material.

Syngas Underground Coal Gasification (UCG) Testing of Fracture Type Subbituminous Coal in Laboratory Scale

Underground Coal Gasification is a method used to convert underground coal seams into a gaseous product commonly called synthetic gas through a flammable chemical process without going through a conventional mining process. The UCG concept was first developed in England which was then continued by the Soviet Union in field trials of UCG which was used as a power plant. In Indonesia, Tekmira has begun to research UCG, but there are very few publications on UCG. Therefore, it is necessary to conduct research on laboratory scale UCG for analysis of gas products to support the study of renewable energy. UCG testing begins with sample preparation followed by laboratory-scale coal gasification testing. There is a sample of coal used in the test, namely Subbituminous Coal from Tanjung Enim, South Sumatra. Initial combustion is carried out by flowing propane gas into the reactor tube using a burner. Furthermore, a mixture of oxygen gas and compressed air is used to keep the coals burning. After obtaining the gas from the combustion, then gas sampling is carried out using a suction pump which will be stored in a tedlar gas bag. Combustion gas products will be checked for syngas concentration using a Gas Chromatography tool to determine the concentration of CH4, CO2 and O2 gases. From the tests that have been carried out, the gas concentrations of O2 are 3.67%, CO2 41.51%, and CH4 6.93%. Coal in the confined test conditions has good conditions with indications of seeing the concentration of CH4, O2, and CO2 gas.

Pre-combustion gas separation by ZIF-8-polybenzimidazole mixed matrix membranes in the form of hollow fibres—long-term experimental study

Polybenzimidazole (PBI) is a promising and suitable membrane polymer for the separation of the H 2 /CO 2 pre-combustion gas mixture due to its high performance in terms of chemical and thermal stability and intrinsic H 2 /CO 2 selectivity. However, there is a lack of long-term separation studies with this polymer, particularly when it is conformed as hollow fibre membrane. This work reports the continuous measurement of the H 2 /CO 2 separation properties of PBI hollow fibres, prepared as mixed matrix membranes with metal-organic framework (MOF) ZIF-8 as filler. To enhance the scope of the experimental approach, ZIF-8 was synthesized from the transformation of ZIF-L upon up-scaling the MOF synthesis into a 1 kg batch. The effects of membrane healing with poly(dimethylsiloxane), to avoid cracks and non-selective gaps, and operation conditions (use of sweep gas or not) were also examined at 200°C during approximately 51 days. In these conditions, for all the membrane samples studied, the H 2 permeance was in the 22–47 GPU range corresponding to 22–32 H 2 /CO 2 selectivity values. Finally, this work continues our previous report on this type of application (Etxeberria-Benavides et al . 2020 Sep. Purif. Technol. 237 , 116347 ( doi:10.1016/j.seppur.2019.116347 )) with important novelties dealing with the use of ZIF-8 for the mixed matrix membrane coming from a green methodology, the long-term gas separation testing for more than 50 days and the study on the membrane operation under more realistic conditions (e.g. without the use of sweep gas).

Combustion Characteristics of Multi-Element Swirl Coaxial Jet Injectors under Varying Momentum Ratios

The combustion characteristics of a staged combustion cycle engine with an oxidizer-rich preburner were experimentally studied at different momentum ratios of multi-element injectors. Propellants were simultaneously supplied as a liquid–liquid–liquid system, and an injector was designed in which a swirl coaxial jet is sprayed. The injector burned the propellants in the inner chamber which had a temperature greater than 2000 K. To cool the combustion gas, a liquid oxidizer was supplied to the cooling channel outside the injector. To prevent the turbine blades from melting, the temperature of the combustion gas was maintained below 700 K. To confirm the combustion characteristics at different momentum ratios of the high-temperature combustion gas inside the injector and the low-temperature liquid oxidizer outside the injector, three types of injectors were designed and manufactured with different momentum ratios: MR 3.0, MR 3.3, and MR 3.7. In this study, the results of the combustion test for each type were compared for 30 s. For ORPB-A, a combustion pressure of 18.5 MPaA, fuel mass flow rate of 0.26 kg/s, oxidizer mass flow rate of 15.3 kg/s, and turbine inlet temperature of 686 K were obtained in the combustion stability period of 29.0–29.5 s. The combustion efficiency was 98% for MR 3.0 (ORPB-A), which was superior to that for other momentum ratios. In addition, during the combustion test for MR 3.0, the fluctuations in the characteristic velocity, combustion pressure, and propellant mass flow rate were low, indicating that combustion was stable. The three types of combustion instability were all less than 0.8%, thus confirming that the combustion stability was excellent.