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The vessel wall response shows a good agreement between the numerical predictions of and experimental data using the limit load approach. Further work is continuing to understand the thermohydraulic response and the boundary conditions for material modelling. As shown in figure 2 there was one BLEVE of a bare tank containing a PRV, highlighting the risk of serious consequences if models are inaccurate. The behavior of partly coated tanks were similar to the bare tank.
The results are based on data1. Figure 3 displays temperatures of the tank wall and of the gas phase over testing time. It can be seen that a complete coating strongly delayed the heating of tank wall and gas phase, whereas the partly coated tanks only had a minor influence on temperature development. There was no significant difference between a half coated and a thirdly coated tank measurable. Figure 4 shows the internal pressure of tanks over testing time. Only the fully coated tank enabled a low pressure over 90 min testing time. Hence, a complete coating is necessary to guarantee the fire safety of hazmat tanks and a partly coating is not sufficient.
It was possible to achieve an error as 9% or even 0% at certain time steps, as shown in the graph above, the usage of UDF code has major importance in achieving the pressure Profile required, and it heat transfer between the bottle itself and the surroundings was taken into consideration which of course had a high influence on how the temperature of the air flask changes.
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.
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.