Flow structure and heat transfer between a swirled impinging jet and dimple

Paper presented at the 9th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Malta, 16-18 July, 2012.dc201

Modelling of pulsed air jet impingement heat transfer in a single-phase and gas-droplets mist jet

Paper presented at the 9th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Malta, 16-18 July, 2012.The flow structure and heat transfer of an intermittent impinging single-phase air and water mist jet with low mass fraction of droplets (not more than 1 %) is studied numerically. In the range of small distances between the tube edge and obstacle H/(2R) ≤ 6 in the pulsed jet heat transfer at stagnation point increases with a rise of pulse frequency, whereas at high distances H/(2R) > 8 frequency rise causes heat transfer reduction. Heat transfer intensity during flow pulse action increases and exceeds significantly the corresponding value for the stationary case. When there is no flow, the value of Nusselt number decreases considerably. Results obtained were compared with available data of other authors, and satisfactory agreement was obtained for the influence of pulse frequency on heat transfer of the gas jet with impinging surface.dc201

Studies and application of bent crystals for beam steering at 70-GeV IHEP accelerator

This report overviews studies accomplished in the U70 proton synchrotron of IHEP-Protvino during the recent two decades. Major attention is paid to a routine application of bent crystals for beam extraction from the machine. It has been confirmed experimentally that efficiency of beam extraction with a crystal deflector of around 85% is well feasible for a proton beam with intensity up to 1012 protons per cycle. Another trend is to use bent crystals for halo collimation in a high energy collider. New promising options emerge for, say, LHC and ILC based on the "volume reflection" effect, which has been discovered recently in machine study runs at U70 of IHEP (50 GeV) and SPS of CERN (400 GeV).Comment: 12 pages, 14 figure

Crystal collimation experiment on 70-GeV proton accelerator

The first proof-of-principle experiment on "crystal collimation" was performed with 70-GeV protons on IHEP accelerator. A bent crystal installed in the ring as a primary element upstream of a collimator has reduced the radiation levels downstream in the accelerator by a factor of two. The measurements agree with Monte Carlo predictions

Proton Extraction from IHEP Accelerator Using Bent Crystals

IHEP Protvino has pioneered the wide practical use of bent crystals as optical elements in high-energy beams for beam extraction and deflection on permanent basis since 1989. In the course of IHEP experiments, crystal channeling has been developed into efficient instrument for particle steering at accelerators, working in predictable, reliable manner with beams of very high intensity over years. Crystal systems extract 70 GeV protons from IHEP main ring with efficiency of 85% at intensity of 1.E12, basing on multi-pass mechanism of channeling proposed theoretically and realised experimentally at IHEP. Today, six locations on the IHEP 70-GeV main ring of the accelerator facility are equipped by crystal extraction systems, serving mostly for routine applications rather than for research and allowing a simultaneous run of several particle physics experiments, thus significantly enriching the IHEP physics program. The long successful history of large-scale crystal exploitation at IHEP should help to incorporate channeling crystals into accelerator systems worldwide in order to create unique systems for beam delivery. We report recent results from the research and exploitation of crystal extraction systems at IHEP.Comment: Invited talk at the International workshop "Relativistic Channeling and Related Coherent Phenomena", Frascati (Rome) 23-26 March 200