Numerical simulation of the internal flow field for the straight pipeline after a sonic nozzle and its influence on the discharge coefficient
By establishing the model, a nozzle outlet and its internal flow field for the straight pipeline after the sonic nozzle is simulated by the CFD software. The simulation results are compared with theoretical data and experimental tests respectively. According to the simulation results, pressure changes strongly from the nozzle outlet, and gradually rises to the back pressure after a distance of 3D (D is pipe diameter) from the nozzle outlet. With the 5D length of the straight pipeline after a sonic nozzle, the nozzle throat will keep critical flow when the back pressure ratio is less than or equal to 0.849, and the straight pipeline after a sonic nozzle has little influence on the discharge coefficient. But when the back pressure ratio is less than 0.507, the pressure in the pipeline appears fluctuations.
Effects of inlet shapes of critical venturi nozzles on discharge coefficients
Abstract The discharge coefficients of critical venturi nozzles were obtained in a high-pressure gas flow standard system, which was a gravitational weighing system. The calibration uncertainty of a critical venturi nozzle of about 8 mm throat diameter was ±0.08% and ±0.14% at upstream stagnation pressures of 4 MPa and 1 MPa, respectively. The discharge coefficients of critical venturi nozzles fabricated according to ISO specifications are in good agreement with ISO correlation. The discharge coefficients for small inlet radius decrease significantly as the inlet length becomes short, owing to separation at the sharp inlet. For nozzles having long inlet radius, the effects of inlet length on the discharge coefficients were relatively small, but the effects become significant at the short inlet length. The effect of separation at the inlet is stronger than that of the boundary layer growth. The experimental results provide excellent support for the shape of critical venturi nozzles suggested by ISO specifications.
MT and the Swiss language service providers: an analysis and training perspective
Switzerland is perceived as a highly multilingual country, with four national languages and a solid translation tradition in official, administrative and corporate settings, now even extended to include English. A research case study was set up to investigate the understanding and use of translation and language technologies by Swiss language service providers. This paper highlights some findings, particularly focusing upon the issue of translation automation processes in multilingual documentation production, with a view not only to spot preconceptions or knowledge gaps about MT, but also to 
suggest some training principles. We will argue that training activities ought to present MT systems as 
key aiding components of translator workbenches and, their output, as a valid linguistic resource for further human refining, if necessary. Moreover, in line with the idea that MT can be part and parcel of multilingual content production cycles, we will look at the interaction of MT with controlled language, CAT tools and terminology work. In sum, we will make explicit the usefulness of MT against the 
widespread prejudice that investing in MT does not return any benefits given the ‘low and hilarious quality of its output’, as quoted by most of the interviewees of our case study.