Simplified Flow Analysis Research Articles

The influence of selected adjustment parameters on the operation of LPG vapor phase pulse injectors

The investigations aimed at proving the influence of selected parameters on the flow properties of LPG vapor phase injectors. The author mainly assessed the feed pressure, the injector piston lift, the diameter of the outlet nozzle and the realization of the current-modulating signal. Functional relations have been determined and qualitative assessment of the compatibility has been performed. Additionally, an evaluation of the influence of the analyzed parameters has been performed on the injector full opening and closing times that confirms the response to the impulse and may be decisive in the case of short injection times. It has been confirmed that the injector piston lift significantly influences the response times (for full opening - 1.00 ms and full closing – 1.08 ms) and the PWM duty cycle below 50% may lead to a closure of the injector due to insufficient counter force (difference for full closing by 7.53 ms at the 10 ms opening times). In order to measure the response times, an outflow meter has been proposed. A new parameter has been introduced to the analysis – opening timing that may be used in simplified flow analysis. The investigations are a response to the market demands for this type of analyses and to an increasing demand for multipoint LPG vapor phase injection systems. The investigations may turn out useful in calculations or validations of simulation models.

Understanding virtual water flows: A multiregion input‐output case study of Victoria

This article explains and interprets virtual water flows from the well‐established perspective of input‐output analysis. Using a case study of the Australian state of Victoria, it demonstrates that input‐output analysis can enumerate virtual water flows without systematic and unknown truncation errors, an issue which has been largely absent from the virtual water literature. Whereas a simplified flow analysis from a producer perspective would portray Victoria as a net virtual water importer, enumerating the water embodiments across the full supply chain using input‐output analysis shows Victoria as a significant net virtual water exporter. This study has succeeded in informing government policy in Australia, which is an encouraging sign that input‐output analysis will be able to contribute much value to other national and international applications.

Audio–video fire-detection of open fires

In the scope of the development of a video-based fire detection system, investigations on the dynamic behaviour of open flames have been made [Schultze. Untersuchungen zur Audio-Video-Detektion von offenen Bränden, Diploma thesis, Duisburg, 2003]. Standardised fires were recorded with different audio and video systems and their flow and flickering analysed. The analyses show that the flickering of flames is not only viewable in the video data, but also detectable in the acoustic recordings. Using a block-based motion estimator it is possible to trace the movements of flames. Due to the high velocity of flame movements this motion estimation is however only successful in high speed recordings. Therefore a simplified flow analysis has been developed in order to trace the characteristic pumping movement of flame balls in turbulent open flames. The simplified flow analysis is applicable on usual video recordings and should be considered for implementation in an automatic flame detection system.

TRANSMITTING TORQUE CALCULATION OF THE ROTARY BLADE COUPLING FOR 4WD VEHICLES

The Rotary Blade Coupling (RBC) is a type of torque split couplings for 4-Wheel Drive (4WD) vehicles. RBC unit mainly consists of a wet multi-disk clutch and a pressure chamber with the blade rotating in high viscosity silicone oil. The pressure chamber generates clutch engaging hydraulic force, which depends on the differential speed between the input and the output shaft. The high viscosity silicone oil in the pressure chamber exhibits non-Newtonian fluid properties. This report presents the simplified flow analysis as the practical designing tool. Effects of non-Newtonian fluid properties of silicone oil are considered. Also the heat transfer modeling during the coupling operation is included in the calculation. Typical blade shape calculations and the experimental results to insure the analysis are shown.

Development of polymer blend morphology during compounding in a twin‐screw extruder. Part IV: A new computational model with coalescence

AbstractIn Part II of this series of publications, the first generation model of morphology evolution during polymer blending in a twin‐screw extruder was presented. The model was based on a simplified flow analysis, and an assumption that dispersion occurs via drop fibrillation followed by disintegration. In the present Part IV, several modifications of the model are discussed. (i) The flow analysis was refined by computing the pressure profiles. (ii) The flow paths and strain history of the dispersed droplets within the screw elements are computed directly, which makes it possible to determine the drop susceptibility to deformation and break. (iii) Besides the fibrillation mechanism, a drop‐splitting mechanism for low supercritical capillary numbers is incorporated. (iv) The choice of breakup mechanism is based on micro‐rheological criteria. (v) The coalescence effects are taken into account. (vi) The theoretical model is self‐consistent, without adjustable parameters. The validity of theoretical assumptions was evaluated by comparing the model predictions with the experimental droplet diameters at different positions in the twin‐screw extruder.