The ALBA Synchrotron Light Facility crotch absorbers, that remove the unused storage ring radiati... more The ALBA Synchrotron Light Facility crotch absorbers, that remove the unused storage ring radiation, incorporate an internal cooling system composed by a number of parallel pinholes and by the corresponding stainless steel inner tubes inserted into each of them. Water flows in the resulting annular sections to evacuate the total heat power. Around each inner tube, a spiral wire is fixed along the whole length with a given pitch height in order to enhance the convection heat transfer. The influence of several design parameters on the absorber thermo-fluid behavior has been evaluated by means of the CFD software ANSYS CFX. In particular, the wall heat transfer coefficients and the pressure losses through a single pinhole have been evaluated for a range of different flow rates and pitch heights. Moreover, some modifications of the end wall geometry have been simulated as well as the effect of reversing the flow direction inside the channels. Finally, the critical crotch absorber type 3...
The ALBA Synchrotron Light Source cooling system is designed with a common return pipe that inter... more The ALBA Synchrotron Light Source cooling system is designed with a common return pipe that interconnects the four consumption rings. Such configuration is believed to compromise its optimal operation. To understand its thermo-fluid dynamic behaviour, a detailed 1D model has been built comprising all the components such as the pipes, fittings, bends, valves, pumping stations, heat exchangers and so on, and the various regulation mechanisms. Preliminarily, the model results in steady state operating conditions have been compared with experimental measurements and the maximum deviations have been found below 13%. Then, a series of transient numerical simulations have been carried out to determine the system response. Specifically, effects of the blockage and leakage of a consumption line as well as the increase and decrease of heat duty for the tunnel rings have been investigated. As a result, the stability of the system has been evaluated and the operational limits have been estimate...
ALBA is a 3 GeV, 268.8 m storage ring with extended Double Bend Achromat (DBA) structure under co... more ALBA is a 3 GeV, 268.8 m storage ring with extended Double Bend Achromat (DBA) structure under construction near Barcelona, Spain. With the design current of 400 mA, a total power of 407 kW is radiated by the circulating beam from the bending magnets. The design of the vacuum system was done by using the concept of the "crotch absorbers" which is used in many modern synchrotron light sources. These absorbers are not only going to absorb the power of the unused radiation but also will allow fast vacuum conditioning. 156 absorbers are need all around the machine in order to guarantee that no radiation will hit the chamber walls, the absorbers are grouped into three types, several design criteria have been studied in order to create our own one which is based on the number of allowed cycles before failure with the concept of the strain values. Finite element analysis (FEA) has been performed to estimate the stress, strain, maximum overall temperature and the maximum cooling temperature for all the types. The results for the critical absorber (type 3) under conservative conditions: max. overall temperature is 312.8°C, max. strain is 0.099% and max. stress is 112.3 MPa. With this strain, the absorber can withstand up to 1.10 5 cycles of operation.
ALBA will be a third generation synchrotron light facility to be built near Barcelona (Spain). Th... more ALBA will be a third generation synchrotron light facility to be built near Barcelona (Spain). The design phase of ALBA is almost completed and the first components are ready to be ordered. Commissioning of the storage ring is foreseen to start at the end of 2008. The circumference of the storage ring of ALBA is 268.8 m and it will be divided into 16 vacuum sections by ultra high vacuum (UHV) gate valves. The vacuum chamber will be made of stainless steel with vertical aperture of 28 mm and 72 mm width. The vacuum chamber will be connected to an antechamber with a slot of 10 mm height. The antechamber will have the crotch absorbers which will absorb the unwanted synchrotron radiation. The pumping will be by sputter ion pumps (SIP), NEG pumps and titanium sublimation pumps (TSP), with an overall pumping speed from SIP of 57,400 l/s. This will maintain an average dynamic pressure of around 1 Â 10 À9 mbar to achieve a beam lifetime >15 h at the designed current.
The ALBA Synchrotron Light Facility crotch absorbers, that remove the unused storage ring radiati... more The ALBA Synchrotron Light Facility crotch absorbers, that remove the unused storage ring radiation, incorporate an internal cooling system composed by a number of parallel pinholes and by the corresponding stainless steel inner tubes inserted into each of them. Water flows in the resulting annular sections to evacuate the total heat power. Around each inner tube, a spiral wire is fixed along the whole length with a given pitch height in order to enhance the convection heat transfer. The influence of several design parameters on the absorber thermo-fluid behavior has been evaluated by means of the CFD software ANSYS CFX. In particular, the wall heat transfer coefficients and the pressure losses through a single pinhole have been evaluated for a range of different flow rates and pitch heights. Moreover, some modifications of the end wall geometry have been simulated as well as the effect of reversing the flow direction inside the channels. Finally, the critical crotch absorber type 3...
The ALBA Synchrotron Light Source cooling system is designed with a common return pipe that inter... more The ALBA Synchrotron Light Source cooling system is designed with a common return pipe that interconnects the four consumption rings. Such configuration is believed to compromise its optimal operation. To understand its thermo-fluid dynamic behaviour, a detailed 1D model has been built comprising all the components such as the pipes, fittings, bends, valves, pumping stations, heat exchangers and so on, and the various regulation mechanisms. Preliminarily, the model results in steady state operating conditions have been compared with experimental measurements and the maximum deviations have been found below 13%. Then, a series of transient numerical simulations have been carried out to determine the system response. Specifically, effects of the blockage and leakage of a consumption line as well as the increase and decrease of heat duty for the tunnel rings have been investigated. As a result, the stability of the system has been evaluated and the operational limits have been estimate...
ALBA is a 3 GeV, 268.8 m storage ring with extended Double Bend Achromat (DBA) structure under co... more ALBA is a 3 GeV, 268.8 m storage ring with extended Double Bend Achromat (DBA) structure under construction near Barcelona, Spain. With the design current of 400 mA, a total power of 407 kW is radiated by the circulating beam from the bending magnets. The design of the vacuum system was done by using the concept of the "crotch absorbers" which is used in many modern synchrotron light sources. These absorbers are not only going to absorb the power of the unused radiation but also will allow fast vacuum conditioning. 156 absorbers are need all around the machine in order to guarantee that no radiation will hit the chamber walls, the absorbers are grouped into three types, several design criteria have been studied in order to create our own one which is based on the number of allowed cycles before failure with the concept of the strain values. Finite element analysis (FEA) has been performed to estimate the stress, strain, maximum overall temperature and the maximum cooling temperature for all the types. The results for the critical absorber (type 3) under conservative conditions: max. overall temperature is 312.8°C, max. strain is 0.099% and max. stress is 112.3 MPa. With this strain, the absorber can withstand up to 1.10 5 cycles of operation.
ALBA will be a third generation synchrotron light facility to be built near Barcelona (Spain). Th... more ALBA will be a third generation synchrotron light facility to be built near Barcelona (Spain). The design phase of ALBA is almost completed and the first components are ready to be ordered. Commissioning of the storage ring is foreseen to start at the end of 2008. The circumference of the storage ring of ALBA is 268.8 m and it will be divided into 16 vacuum sections by ultra high vacuum (UHV) gate valves. The vacuum chamber will be made of stainless steel with vertical aperture of 28 mm and 72 mm width. The vacuum chamber will be connected to an antechamber with a slot of 10 mm height. The antechamber will have the crotch absorbers which will absorb the unwanted synchrotron radiation. The pumping will be by sputter ion pumps (SIP), NEG pumps and titanium sublimation pumps (TSP), with an overall pumping speed from SIP of 57,400 l/s. This will maintain an average dynamic pressure of around 1 Â 10 À9 mbar to achieve a beam lifetime >15 h at the designed current.
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