The nozzle shape was investigated in order to develop a high performance nozzle for pulsed Nd:YAG laser cutting, and its effect on fine cutting of thin metal plate was also discussed. In the case of 0.5mm throat diameter Laval throat nozzle with an initial expansion zone, the pressure on workpiece increased, and the straightness of gas flow was improved compared to a traditional straight throat...

A model of a linear aerospike rocket nozzle that consists of coupled aerodynamic and structural analyses has been developed. A nonlinear computational fluid dynamics code is used to calculate the aerodynamic thrust, and a three-dimensional finite-element model is used to determine the structural response and weight. The model will be used to demonstrate multidisciplinary design optimization (MD...

The occurrence of vortices in the sac volume automotive multi-hole fuel injectors plays an important role development vortex cavitation, which directly influences flow structure and emerging sprays that, turn, influence engine performance emissions. In this study, RANS-based turbulence modelling approach was used to predict internal a vertical axis-symmetrical (6) diesel injector under non-cavi...

Acoustic analogues of black holes (dumb holes) are generated when a supersonic fluid flow entrains sound waves and forms a trapped region from which sound cannot escape. The surface of no return, the acoustic horizon, is qualitatively very similar to the event horizon of a general relativity black hole. In particular Hawking radiation (a thermal bath of phonons with temperature proportional to ...

Background: Oral feeding problems are among the most common issues in preterm infants. Various methods and feeding support tools are used in this regard, such as cup feeding and feeding nozzle. The present study aimed to determine the preferred method between cup feeding and feeding nozzle to support oral feeding in premature neonates. Methods: This clinical trial was conducted on 70 preterm i...

Static electromagnetic braking (EMBr) fields affect greatly the turbulent flow pattern in steel continuous casting, which leads to potential benefits such as decreasing flow instability, surface defects, and inclusion entrapment if applied correctly. To gain a fundamental understanding of how EMBr affects transient turbulent flow, the current work applies large eddy simulations (LES) to investi...

\nG ABSTRACT An abrasive waterjet nozzle wear monitoring and compensating mechanism using the frequency domain.acoustic signals geneiated by the jet exiting the nozzle, as input, is prbposed. An artificial neural network which forms the critical iart of this system is developed using the _back-propagatlon algorithm. The trained network is capable of determining the nozzle diameter corresponding...

An experimental study was performed to measure surface Nusselt number and film cooling effectiveness on a film cooled first stage nozzle guide vane using a transient thin film gauge (TFG) technique. The information presented attempts to further characterize the performance of shaped hole film cooling by taking measurements on a row of shaped holes downstream of leading edge showerhead injection...

We develop a case breach model for the on-board fault diagnostics and prognostics system for subscale solid-rocket boosters (SRBs). The model development was motivated by recent ground firing tests, in which a deviation of measured time-traces from the predicted time-series was observed. A modified model takes into account the nozzle ablation, including the effect of roughness of the nozzle sur...