ЧИСЛЕННОЕ И ЭКСПЕРИМЕНТАЛЬНОЕ ИСЛЕДОВАНИЕ ГИДРАВЛИЧЕСКОГО СОПРОТИВЛЕНИЯ ТРУБ С ВНУТРЕННИМ СПИРАЛЬНЫМ ОРЕБРЕНИЕМ, НАНЕСЕННЫМ МЕТОДОМ ДЕФОРМИРУЮЩЕГО РЕЗАНИЯ

An object of investigation is a tube having helical fins on the internal surface and different geometric sizes. Investigation methods: experiments to obtain quantitative results hydraulic resistance of tubes with internal helical finning and to verify computational algorithm; numerical simulation to visualize the flow structure in the tube. Studies of hydraulic resistance of tubes with internal helical finning over a wide range of operating and geometric parameters were made: ReD=2⋅103...2.5⋅105, under the variation of the angle of swirling a = 14–87°, the relative height of a protrusion h/d = (25–87,5)⋅10–3, the relative axial pitch p/d = 0.16–12.73. It is revealed that the hydraulic resistance of tubes with helical finning increases by a factor of 1.1 to 11.7. The numerical simulation results showed that, as the angle of helical swirling is increased, in the near-wall layers the share of the circumferential velocity component increases and the share of the longitudinal component decreases. And since the finning height exceeds the boundary layer thickness, the hydraulic resistance grows.В данной работе объектом исследования являются трубы с внутренним спиральным оребрением с различными геометрическими размерами. Методы исследования: эксперимент – для получения количественных результатов по гидравлическому сопротивлению труб с внутренним спиральным оребрением и для верификации расчетного алгоритма; численное моделирование – для визуализации структуры течения в трубе. Изучено гидравлическое сопротивления труб с внутренним спиральным оребрением в широком диапазоне режимных и конструктивных параметров: ReD = 2⋅103...2,5⋅105, при изменении угла закрутки a = 14–87°, относительной высоты выступов h/d = (25–87,5)⋅10–3, относительного шага по оси p/d = 0,16–12,73. Выявлено увеличение гидравлического сопротивления труб с внутренним спиральным оребрением от 1,1 до 11,7 раза. Результаты проведенного численного моделирования показали, чтос увеличением угла спиральной закрутки в пристеночных слоях доля окружной составляющей скорости увеличивается, а доля продольной составляющей скорости уменьшается. Так как высота оребрения превышает толщину пограничного слоя, то в результате растет гидравлическое сопротивление

Response of the ATLAS tile calorimeter prototype to muons

A study of high energy muons traversing the ATLAS hadron Tile calorimeter in the barrel region in the energy range between 10 and 300~GeV is presented. Both test beam experimental data and Monte Carlo simulations are given and show good agreement. The Tile calorimeter capability of detecting isolated muons over the above energy range is demonstrated. A signal to background ratio of about 10 is expected for the nominal LHC luminosity ($10^{34} cm^{-2} sec^{-1}$). The photoelectron statistics effect in the muon shape response is shown. The e/mip ratio is found to be $0.81 \pm 0.03$; the e/$\mu$ ratio is in the range 0.91 - 0.97. The energy loss of a muon in the calorimeter, dominated by the energy lost in the absorber, can be correlated to the energy loss in the active material. This correlation allows one to correct on an event by event basis the muon energy loss in the calorimeter and therefore reduce the low energy tails in the muon momentum distribution

Evaluation of Fermi Read-out of the ATLAS Tilecal Prototype

Prototypes of the \fermi{} system have been used to read out a prototype of the \atlas{} hadron calorimeter in a beam test at the CERN SPS. The \fermi{} read-out system, using a compressor and a 40 MHz sampling ADC, is compared to a standard charge integrating read-out by measuring the energy resolution of the calorimeter separately with the two systems on the same events. Signal processing techniques have been designed to optimize the treatment of \fermi{} data. The resulting energy resolution is better than the one obtained with the standard read-out

A measurement of the energy loss spectrum of 150 GeV muons in iron

The energy loss spectrum of 150 GeV muons has been measured with a prototype of the ATLAS hadron calorimeter in the H8 beam of the CERN SPS.\\ The differential probability $dP/dv$ per radiation length of a fractional energy loss $v = \Delta E_{\mu} / E_{\mu}$ has been measured in the range $v = 0.01 \div 0.95$; it is then compared with the theoretical predictions for energy losses due to bremsstrahlung and production of electron-positron pairs or of energetic knock-on electrons.\\ The integrated probability $\int_{0.01}^{0.95} (dP/dv) dv$ is $(1.610\pm0.015_{stat.}\pm0.105_{syst.})\cdot10^{-3}$ in agreement with the theoretical predictions of $1.556\cdot10^{-3}$ and $1.619\cdot10^{-3}$. %7.8.96 - start Agreement with theory is also found in two intervals of $v$ where production of electron-positron pairs and knock-on electrons dominates. In the region of bremsstrahlung dominance ($v = 0.12\div0.95$) the measured integrated probability $(1.160\pm0.040_{stat}\pm0.075_{syst})\cdot 10^{-4}$ is in agreement with the theoretical value of $1.185 \cdot 10^{-4}$, obtained using Petrukhin and Shestakov's \cite{PS} description of the bremsstrahlung process. The same result is about 3.6 standard deviations (defined as the quadratic sum of statistical and systematic errors) lower than the theoretical prediction of $1.472\cdot 10^{-4}$, obtained using Tsai's \cite{TS} description of bremsstrahlung

Results from a combined test of an electromagnetic liquid argon calorimeter with a hadronic scintillating-tile calorimeter

The first combined test of an electromagnetic liquid argon accordion calorimeter and a hadronic scintillating-tile calorimeter was carried out at the CERN SPS. These devices are prototypes of the barrel calorimeter of the future ATLAS experiment at the LHC. The energy resolution of pions in the energy range from 20 to 300~GeV at an incident angle $\theta$ of about 11$^\circ$ is well-described by the expression \sigma/E = ((46.5 \pm 6.0)\%/\sqrt{E} +(1.2 \pm 0.3)\%) \oplus (3.2 \pm 0.4)~\mbox{GeV}/E. Shower profiles, shower leakage, and the angular resolution of hadronic showers were also studied

Mechanical construction and installation of the ATLAS tile calorimeter

This paper summarises the mechanical construction and installation of the Tile Calorimeter for the ATLAS experiment at the Large Hadron Collider in CERN, Switzerland. The Tile Calorimeter is a sampling calorimeter using scintillator as the sensitive detector and steel as the absorber and covers the central region of the ATLAS experiment up to pseudorapidities +/- 1.7. The mechanical construction of the Tile Calorimeter occurred over a period of about 10 years beginning in 1995 with the completion of the Technical Design Report and ending in 2006 with the installation of the final module in the ATLAS cavern. During this period approximately 2600 metric tons of steel were transformed into a laminated structure to form the absorber of the sampling calorimeter. Following instrumentation and testing, which is described elsewhere, the modules were installed in the ATLAS cavern with a remarkable accuracy for a structure of this size and weight