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Future generation gas turbine combustors for power production are expected to have the capability of operating on a variety of different types of fuels. Energy systems running on different fuels produce flames with different burning behaviors, combustion dynamics, and pollutant emissions than when using conventional fuels. To ensure the implementation of new energy sources for future power generation units, which is critical for the US energy sector, lab-scale studies at high pressures and temperatures are being performed at many different locations throughout the world. Although many of these authors in the past present their results from the use of a high-pressure combustor, none have made their design methodology available to the public. Therefore, this paper presents a design of an optically accessible high-pressure combustor facility based on a 500 kW power and 1.5 MPa capability, which is the representative pressure of a gas turbine. Finite element analysis was extensively used to predict window and wall thicknesses needed to withstand these extreme conditions. Based on stress analysis quartz windows were designed with a thickness of 48 mm and a thickness of 8.61 cm was selected for the stainless steel combustor. Follow-up on testing using the high-pressure gas turbine combustor using various different types of fuels, diluents, and injectors have provided repeatable data on the capability of the combustor design to withstand the extreme environment conditions.

This work is focused on investigation of thermal efficiency of a Hypersonic scramjet engine and propose some improvement of thermal efficiency based on thermodynamic and fluid flow analysis. Thermal management system is one of the main research fields in scramjet design. As it has no moving parts, the total thermal efficiency depends on inlet conditions, conditions of combustor exit and conditions of the engine exit. A combustor exit condition dictates the velocity and temperature after combustion. we concentrate our focus on this section. The first part of the paper, we tried to describe the fundamental exergy relationship for scramjet and we developed the relation of exergy distribution and exergy delivery rate. From an extensive literature review, we have found the relations between fluid velocity, pressure and temperature, which is described in the later part of the paper. Our main focus is to develop a combined relation of thermal efficiency in terms of engine exit velocity, temperature and air-fuel ratio. Different characteristic parameters such as overall efficiency, thermal efficiency, specific impulse have been determined at different inlet temperature ratio or the cycle static temperature ratio (T3/T0) and an optimum inlet temperature ratio is proposed for maximum overall efficiency.

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Although thermoplastics possess many desirable traits as solidified materials, they are combustible and burn readily. Post burning samples of polymethylmethacrylate (PMMA) are the focus of this study. During flame spread, PMMA forms a bubble containing molten surface layer that influences the spread rate and the surface mass efflux. This study examines the formation and distribution of bubbles inside a PMMA sample that has previously been subjected to flame spread and then re‐hardened into its solid state. Experiments discussed herein were conducted in a Narrow Channel Apparatus (NCA), which reduces the influences of gravitation (buoyancy) on flame spread. Bubble sizes and counts were determined using digital image analysis (DIA). The burnt samples were analyzed by dividing sample images into eight equal area sections. Frequency distributions of bubble size (area) were compared. Distribution functions were fitted against the empirical probability density function (PDF) for the bubble size distribution. The log‐normal distribution predicts the bubble size distribution for all segments. The bubble distribution function can be used to describe physical processes inside the polymeric material as it undergoes thermal transformation by the spreading flame.