Optimization of working roll cooling in hot rolling

Paper presented at the 9th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Malta, 16-18 July, 2012.The cooling of working rolls is an important process in the hot rolling technology. The optimal cooling of rolls should be designed with respect to two aspects. The first is the wearing of a roll where high temperature decreases the durability of the surface layer. The second aspect is a thermal deformation of a roll. This is critical for the shape and tolerance of flat products. Cooling at rolling mill should be designed with consideration to both aspects. Finding optimum pressure and flow rate is a difficult task. In regards to water quantity, the experience shows that the phrase “more is better” is not valid here. In other word – an increase in the amount of water can even cause a decrease in cooling intensity. Water nozzles are typically used in this case. There are many of factors which can influence the efficiency of the nozzle cooling system: Type of a nozzle, geometrical configuration (nozzle pitch, distance from the roll, orientation, number of manifolds), coolant pressure and temperature. Cooling intensity is mostly specified through Heat transfer coefficient (HTC) or heat flux (HF) distribution. Coolant flow on the rotating roll surface makes the problem complex. Surface temperature of the cylinder plays an important role in the heat transfer mechanism, especially for higher temperatures where boiling must be considered. No analytical or numerical solution of heat transfer and fluid flow for this case is known. The task can be successfully solved experimentally. An experimental bench and methodology of realistic boundary conditions determination was developed in the Heat Transfer and Fluid Flow Laboratory (HEATLAB). The strategy of optimization is based on two steps. First is investigation of present situation of work roll cooling system and second is design of a new system. Criterion of optimization is saving of cooling water with remaining or increasing of cooling intensity. Comparison of the original design and new design was done numerically, using special software and experimentally by temperature measurement of working roll after specified rolling campaign. Optimized cooling system was applied on hot flat rolling mill in voestalpine Stahl GmbH.dc201

FATIMA Czech pilot

In FATIMA project, a pilot site in Czechia was established to demonstrate how precision agriculture may serve for optimizing crop yields as well as for protection of water quality, since the pilot is located in Czech largest drinking water reservoir catchment. The pilot site Dehtáře is situated in the south-west Bohemo-Moravian Highland. The site contains tile drainage and is of very heterogeneous soil conditions; from shallow, light and stony Haplic Cambisols to heavy Haplic Gleysols, with profoundly different water regimes. For the field trial (spring barley in 2016), crop yield potential was determined from crop statuses as captured by satellite images) eight years back, assessed by Enhanced Vegetation Index. Based on this, as well as on a detailed soil survey and repeated soil sampling, variable fertilizer application zones (70 – 120%) were delineated and mineral fertilizers distributed accordingly with GPS operated spreader three times from late April to late May. The rest of the site was fertilized uniformly. Soil water regime (soil moisture, soil water potential) was monitored continuously on eight spots and real-time broadcasted by wireless sensor network to WEB GIS interface via SensLog solution, adopted from FOODIE project. In the same spots, soil water was sampled by gravitational soil lysimeters. Precise harvest showed a general agreement with the delineated application zones and yield potential, however, some ambiguities were revealed, most probably due to changeable soil water regime, as documented by the sensors, as well as due to variable soil chemical properties (low soil pH). Nevertheless, precisely applied fertilizer doses in the application zones brought about 10% higher crop yields with simultaneous better N crop efficiency. Soil water quality samples confirmed that heterogeneous doses of fertilizer in correctly delineated zones is a promising approach for improvement of groundwater quality especially in shallow soils with low water and nutrient retention abilit

Azimuthal anisotropy of heavy-flavor decay electrons in p-Pb collisions at √s_NN = 5.02 TeV

Angular correlations between heavy-flavor decay electrons and charged particles at midrapidity (|η|&lt;0.8) are measured in p-Pb collisions at sNN=5.02 TeV. The analysis is carried out for the 0%-20% (high) and 60%-100% (low) multiplicity ranges. The jet contribution in the correlation distribution from high-multiplicity events is removed by subtracting the distribution from low-multiplicity events. An azimuthal modulation remains after removing the jet contribution, similar to previous observations in two-particle angular correlation measurements for light-flavor hadrons. A Fourier decomposition of the modulation results in a positive second-order coefficient (v2) for heavy-flavor decay electrons in the transverse momentum interval 1.5&lt;pT&lt;4 GeV/c in high-multiplicity events, with a significance larger than 5σ. The results are compared with those of charged particles at midrapidity and those of inclusive muons at forward rapidity. The v2 measurement of open heavy-flavor particles at midrapidity in small collision systems could provide crucial information to help interpret the anisotropies observed in such systems.</p