DESIGN METHODOLOGY OF LONG COMPLEX HELIUM CRYOGENIC TRANSFER LINES

Selected aspects related to the calculations and design of a cryogenic transfer line

Development, design and installation of multichannel transfer lines at W7-X under extreme geometrical constraints

The paper describes achievements in LLRF based tests preparation for superconducting cryo-modules evaluation for European X-ray Free Electron Laser. The software for automatic cryo-modules characterization at the Accelerator Module Test Facility (AMTF) will be presented. In order to identify fundamental working parameters of the eight TESLA cavities cryomodules the scenario of several tests sequence has been proposed and implemented in AMTF. Main parameters like: cavities quenching levels verification, cavities Pi modes identification, slow and fast frequency tuners performance, fundamental power coupler performance, etc are evaluated. Basing on achieved data the decision about module acceptance for work in the linac is done. In this solution the MTCA.4 based LLRF system is used to control and verify cryo-string performance. Middle layer client servers implemented in this environment are responsible for providing tests initial conditions, testing and results archiving in the dedicated data base. Results of described tests are not only vital for module acceptance but are also important for future LLRF system set-up and configuration concerning module work in the accelerator tunnel.

Large scale cryogenic systems applied in modern fusion reactors (Claudet and Aymar 1990), superconducting particle accelerators (Lebrun 1999b; Van-Sciver 1998) or coolant transfer lines (Lebrun 1999a) as well as small scale refrigerators and cryo-coolers generate significant progress in multiple domains related either to material sciences or to structural behaviour. When designing large scale cryogenic systems the engineers quickly realise that it is impossible to build a continuous “cold mass” since the material — by its physical nature — exhibits the thermal contraction and the thermo-mechanical strain fields, developed locally in the constraint structure might damage the object. Thus, any large cryogenic system has to be subdivided into the “cold segments”, each of them constructed separately and all of them assembled together in the destination place. A typical example can be found in the domain of particle accelerators where a continuity of the magnetic field is strongly postulated by the accelerator physics. On the other hand, the real structure has to be discontinuous, since the magnets are limited in length (for technological reasons) and separated by the so-called interconnections (Fig. 1.1). A similar problem appears in the cryogenic transfer lines, that convey liquid nitrogen or helium, where the maximum length of segments is often a function of the technological process of their manufacture and assembly. A typical liquid and gaseous helium transfer line containing several headers, located next to a superconducting accelerator, is shown in Fig. 1.2.

Gas sensing based on the dynamic nonlinear responses of a semiconductor gas sensor: dependence on the range and frequency of a cyclic temperature change

Fatigue of ThO 2 dispersion strengthened nickel alloy with surface modification by Al + ion implantation : Banerjee, R. and Grummon, D.S. Scr. Metall.23, (8), 1249–1254, Aug. 1989

Thermo-mechanical behaviour of energy piles in overconsolidated clay under various mechanical loading levels and thermal cycles

Uniaxial tensile tests were conducted for sintered SiC up to 1400°C in air under static fatigue, low cycle fatigue, static fatigue with cyclic temperature change and synchronized cyclic change of stress and temperature. In all tests, fatigue characteristics were such that time to failure was controlled only by the accumulation of slow crack growth and that no definite acceleration due to cyclic change of either stress or temperature was observed.

This article presents data on the mechanism underlying the nucleation and growth of α‐Sn crystals in mono‐ and polycrystal β‐Sn tin. It is demonstrated that the low temperature deformation and thermocycling (subjection to the cyclic changes of temperature) of the samples of tin (99.9995% Sn) brings to the increase in the α‐Sn crystal nuclestion rate. Kinetics of the nucleation is characterised by the presence of the non‐steady State period tn.On analysing the temperature dependencies of the rate of the α‐Sn centre growth obtained for the planes (100), (001) and (110) it was shown that the mechanism of movement of the interphase boundary depends on the value of the motive force ΔF.

The effect of pigments and additives on the resistance of organic binders to cyclic changes in temperature, humidity, and UV radiation intensity was investigated. The study involved paints based on two binders used in polyurethane paints, pigmented in various shades of yellow, red, and blue. Both the binders and pigments differed in their weather resistance. The color stability, gloss, water contact angle, and surface energy of the coatings were assessed. Changes in color and gloss depended primarily on UV radiation, while decorative properties depended on the type of pigments in each color group. Smaller changes in color and gloss were caused by changes in humidity and temperature, without the contribution of UV radiation. The more weather-resistant pigmentation protected the binder from degradation, as confirmed by FT-IR.

Bio-based insulation materials and their hygrothermal performance in a building envelope system (ETICS)

In an automobile braking system, the heating and cooling cycles that take place on the brake disc surface during braking action lead to thermomechanical fatigue (TMF). TMF, a type of non-isothermal fatigue, occurs when a material experiences simultaneous mechanical and thermal loads. Based on a material’s elastic and plastic deformation, the strain-life technique of fatigue analysis calculates how many TMF cycles a material will withstand before failing. However, it is challenging to effectively recreate the TMF process using conventional testing methods due to the cyclical changes in temperature, stress, and strain. So, in the current situation, all TMF life projections are based mostly on isothermal condition because low-cycle fatigue (LCF) data, which is normally used for design purposes, has been created isothermally. In the present work, a reliable test procedure is adopted to measure the TMF behavior of cast iron grade EN-GJL-250. The novel testing procedure closely resembles the field’s cyclical patterns of temperature and mechanical strain, in addition to online monitoring of the TMF cycles. The testing procedure complies with ISO 12111, ASTM E2368, and the European Code of Practice (CoP). The TMF behavior of EN-GJL-250 was characterized by hysteresis loops and cyclic stress-strain responses. Designers can use test data to help them simulate component behavior and validate current designs through numerical simulations.

Dental restorative material placed in the tooth cavity is exposed to cyclic changes of temperature. The present study aimed to find the effect of thermal cycling on surface hardness, diametral tensile strength and porosity of a visible light cure composite.

Random ionic mobility on blended cements exposed to aggressive environments

The design of the cryogenic system for the 11 GeV/c Super High Momentum Spectrometer (SHMS) is presented. A description of the cryogenic control reservoir and the cryogenic transfer line is given. Details of the cryogenic control reservoirs, cryogenic transfer lines, and pressure piping are summarized. Code compliance is ensured through following the requirements of the ASME Pressure Vessel Code and Pressure Piping Code. An elastic-plastic-analysis-based combined safety factor approach is proposed to meet the low stress requirement of ASME 2007 Section VIII, Division 2 so that Charpy V-notch (CVN) impact testing can be avoided through analysis. Material toughness requirements in ASME 2007 Section VIII, Division 2 are adopted as CVN impact testing rules of stainless steel 304 piping at 4.2 K and 77 K. A formula-based combined safety factor approach for pressure piping is also proposed to check whether the impact testing can be avoided due to low stress. Analysis and calculation have shown that no CVN impact testing of base metal and heat affected zones is required for the helium reservoir, nitrogen reservoir, and their relevant piping. Total heat loads to liquid helium and liquid nitrogen are studied also. The total heat load to LHe for SHMS is estimated to be 137 W, and the total load to LN2 is calculated to be 420 W.