Shock Damage Analysis in Serial Femtosecond Crystallography Data Collected at MHz X-ray Free-Electron Lasers

Serial femtosecond crystallography (SFX) data were recorded at the European X-ray free-electron laser facility (EuXFEL) with protein microcrystals delivered via a microscopic liquid jet. An XFEL beam striking such a jet may launch supersonic shock waves up the jet, compromising the oncoming sample. To investigate this efficiently, we employed a novel XFEL pulse pattern to nominally expose the sample to between zero and four shock waves before being probed. Analyzing hit rate, indexing rate, and resolution for diffraction data recorded at MHz pulse rates, we found no evidence of damage. Notably, however, this conclusion could only be drawn after careful identification and assimilation of numerous interrelated experimental factors, which we describe in detail. Failure to do so would have led to an erroneous conclusion. Femtosecond photography of the sample-carrying jet revealed critically different jet behavior from that of all homogeneous liquid jets studied to date in this manner.

Control Oriented Model for Expander Cycle Scramjet

As a efficient and simple design, expander cycle is widely applied in LRE engineering, but it is seldomly used on scramjet research. In order to establish a complete mathematical model for expander cycle scramjet, a control-oriented model for expander cycle scramjet is proposed in this paper. This model consists of four major parts: combustor, cooling channel, turbo pump and nozzle and gives the result of pressure, temperature, mach number and velocity distribution of combustor and cooling channel and is capable of simulate both pure supersonic combustion mode and supersonic shock wave mode of the combustor. Each part is given by specific mathematical description, which contains the calculation of airflow, combustion, heat transfer and thermal cracking of kerosene. By putting all these parts together, a complete model is formed. This model is proposed to calculate the performance and condition of the engine precisely, comprehensively, swiftly and can be directly used in further study.

Experimental Study Of The Diffusion Combustion Of A High-Speed Round Hydrogen Microjet Part 2. Lifted Flame, Supersonic Flow

Scenario of supersonic diffusion combustion of a round hydrogen microjet is presented in this work. The main features of supersonic diffusion combustion of a hydrogen round microjet are shown: disappearance of a «bottleneck flame» region, lifted flame from the nozzle exit and existence of supersonic «shock cells» in the lifted turbulent flame. The main reason for this scenario of diffusion combustion connected with a temperature factor is found i.e. with existence of thin-walled micronozzles with a small thermal capacity and a possibility of their quenching that doesn't give the chance to exist of the «bottleneck flame» region at big speeds of a microjet efflux. It is shown that with growth of temperature of a micronozzle heating from the «bottleneck flame» region at the same speed of a microjet efflux growth of its spatial size (l/d) is found.

Re-Educating Jet-Engine-Researchers to Stay Relevant

Abstract, jet-engine researchers, designers and operators should follow changing uses of small and large jet engines, especially those anticipated to be used by/in the next generation,In addition, some diminishing returns from isolated, non-integrating, jet-engine component studies, vs. relevant, supersonic, shock waves control inThe central roles of the jet engine as primary or backup flight controller also constitute key relevant issues, especially under post stall conditions involving induced engine-stress while participating in crash prevention or minimal path-time maneuvers to target. [are anticipated to overcome US legislation red-tape that obstructs JES-add-on-emergency-kits-use. [