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Figure 10 illustrates the theoretical results from the simplified model considered, together with the experimental data. These results and measurements are presented one next to the other, in order to facilitate the validity analysis of the proposed simulation methodology.
These results illustrate that the trends are comparable for both sets of data, that is, a similar range is obtained for all of the variables reported. A lower pressure is generated in chamber 5, which is attributed to the shorter length of this chamber. However, such increase in pressure does not correspond exactly to the difference of lengths, as the ratio of lengths would cause a differential pressure of 2.3/1.23 = 1.86, while the ratio of average pressures is on the order of 2. That is, there is an incremental, which is associated to the maximum height attained by the fluid in the chamber. The major difference between both sets of data, the experimental and theoretical, is that the theoretical do not include much of the noise and random oscillations reported in the experimental data. Such noise, however, is of very low amplitude, in comparison with the maximum values attained. The practical applications of these results could be in the area of chamber design, so that the effects of the length of the chambers be taken into account. That is, such greater lengths for the fluid in the chamber would involve larger pressures and consequently, greater stresses. However, the analysis should include an overall perspective, that is, the shortening of the chambers would imply an increase in the number of chambers, for a certain total payload, and the superposition effect of pressures, should be considered. On the other hand, the analysis could be extended to characterize the effects of the distribution of the lengths of the different chambers along the axis of the tanker, as the different resulting forces could have different effects on the pitch response of the road tanker.
There was a need to validate the longitudinal performance required for the cargo securement, as current standards exhibit differences.
A model has been proposed in this paper, to simulate the effect of a shifting cargo on the braking efficiency of the vehicle. Results suggest that the braking efficiency can be greater in the case of a shifting cargo, as a result of the uncoupling of the cargo-vehicle systems, implying that similar braking forces are exerted on a reduced mass. The shifting of the cargo can occur as a result of the vibration of the vehicle, that leads to having a diminished friction force to prevent the shifting of the cargo.
A filling process of the pressure bottle used for the air storage was investigated by numerical simulations. During the filling process, the temperature was rising up to maximal value and after that started to decline. The good match was found between experimental and numerical results. In order to reproduce the experimental conditions, the process of the filling bottle was controlled by the pressure which varied in time. This filling strategy influenced furthermore the mass flow rate and the air flow velocity. Because of the geometrical symmetry, the simulation was calculated as an axisymmetric problem.
Transport safety depends in great extent of what happens to the cargo once the carrying vehicle derails or rollovers. The exposure of tanks to direct fire is a condition that potentially involves catastrophic consequences. Studying the behavior of the contained fluid under these drastic circumstances, is critical to develop methods and techniques to mitigate the serious consequences of many mishaps. In this paper, the experimental potentials of a Particle Image Velocimetry data acquisition system are described, for providing experimental data that could be used to calibrate mathematical models. As an example of the situations that need to be modelled, an experiment is described concerning the effect of the boundary conditions and protecting devices, on the rate of variation of pressure and temperature of the fluid in a tank exposed to a direct fire. In this regard, the results emphasize the importance of equipping the vessels with both thermal insulation and safety valves.
Small and large-scale tests have been carried out Pressure vessel – to improve numerical modelling Different types of fire must be distinguished Modelling of vessels were discussed Test configuration has been developed to see what happens in the vessel First results encourage us to continue the Research Thermohydraulics needs further work (boundary layers).
There was a need to validate the longitudinal performance required for the cargo securement, as current standards exhibit differences. A model has been proposed in this paper, to simulate the effect of a shifting cargo on the braking efficiency of the vehicle. Results suggest that the braking efficiency can be greater in the case of a shifting cargo, as a result of the uncoupling of the cargo-vehicle systems, implying that similar braking forces are exerted on a reduced mass. The shifting of the cargo can occur as a result of the vibration of the vehicle, that leads to having a diminished friction force to prevent the shifting of the cargo.
A novel deign of test equipment has been commissioned to investigate thermal stratification and boiling during fire exposure of pressure vessels. Extensive temperature measurements and video of the internal conditions during fire exposure are possible, and the equipment has been designed for future compatibility with laser-based velocity measurement techniques. It is expected to generate data large quantities of data that will be of use in validation of two- and three-dimensional CFD models for the prediction of pressure vessel behaviour in fire. Future work will seek to characterize the boundary layer conditions in detail for a range of test fluids, fill levels and fire-induced thermal boundary conditions.
Initial tests undertaken during commissioning may indicate that fire exposure of the vessel wall just above the liquid level can have a notable influence on the pressurization rate, by increasing the degree of superheat. Further experimental and modelling work is required to confirm and quantify this effect, or to rebut this conclusion.
The interaction of the vehicles with the pavements imply damaging effects on both systems, as a function of the operating conditions and design characteristics of both systems. These effects influence the road pricing as well as the maintenance costs of the vehicles. In this paper, a simulation scheme has been proposed to analyze such interaction in massive way, involving a multivehicle models was the uncoupling of the roll and pitch responses. Results suggest that the damaging effects on the pavement and the vehicle, depends on the position along the road profile. However, the vertical design of the road would mainly affect the pavement damage, while the turning maneuvers would strongly influence the damage of the vehicle. Many uses can be identified for the proposed simulation scheme, involving different design and operating conditions for both systems.