Micro-Cryogenic Stirling Cooler with a Combined Regenerator and Magnetocaloric Cooling Step
with a Combined Regenerator and Magnetocaloric Cooling Step
A. V. Samvelov1, S. G. Yasev1, A. S. Moskalenko1, V. V. Startsev1, O. V. Pakhomov2
JSC «Opto-mechanical design office «ASTRON», www.astrohn.ru, www.astrohn.com, Lytkarino, Moscow.region, Russia
St. Petersburg University of precision mechanics and optics (ITMO University), www.ifmo.ru, St. Petersburg, Russia
The article describes the developed two-stage microcryogenic Stirling system for cryostatting the photodetector module. The design has a rare-earth combined regenerator in the first stage of cooling and magnetocaloric cooling in the second stage. The design provides an extended range of cryostatting temperatures and an increased efficiency near a temperature of 80K.
Received: 24.06.2019. Accepted: 01.08.2019.
The experts of JSC «Design Bureau «ASTRON» developed a two-stage Stirling microcryogenic system (MCS) for photodetector module (PDM) cryostatting with a rare-earth combined regenerator in the first cooling stage and magnetocaloric (MC) cooling in the second stage. The MCS expander has a built-in active regenerator. The second cooling stage is a rare-earth nozzle of the regenerator and a fixed permanent ring magnet to maintain magnetocaloric cooling. The microcryogenic system is designed to cool the module of the photodetector and provides an extended range of cryostatting temperatures at high efficiency near a temperature of 80K.
The low-temperature stage of the created MCS operates on the basis of the MC effect. It includes a combined regenerator with a nozzle area in the «cold» zone made of rare-earth metal (holmium), the «warm» zone of the regenerator nozzle is filled with elements made of 12X18H10T steel in the form of mesh disks stacked in a package.
Setting up the problem
Rare-earth metals (lanthanides) with special physical properties can be used in modern industrial production to create energy converters. One of these technologies is magnetic cooling, which is based on the MC effect. In recent decades, the interest in studying the MC effect for its use in microcryogenic technology has been increased [1–4]. During this period, many refrigerators, coolers and heat pumps have been developed and patented using both the main and additional cooling stages based on the MC effect implemented with the help of lanthanides. This phenomenon is observed during adiabatic demagnetization of a paramagnetic material with good magnetic properties at temperatures near the Curie (Neel) temperature. In particular, the material has a high MC effect: under isothermal conditions, a working element of this material is magnetized in a magnetic field, being heated at the same time, and then, when a magnetic field is removed, it is demagnetized. In the process of demagnetization, the element, while cooling, provides cryostatting of the object.
The Stirling MCS developed by JSC «Design Bureau «ASTRON» has an active magnetic holmium-based regenerator in the first cooling stage, an MC cooler and fixed permanent magnets in the second cooling stage. The system has reduced power consumption and an extended operating temperature range with increased efficiency near a cryostatting temperature of 80K. In contrast to the known Stirling MCS, there is an additional cooling stage of the cryoagent appears, operating on the MC effect, leading to an increase in the efficiency and expansion of the operating temperature range [5–7].
The research objective was to study the capabilities of the MCS, in the design of which the lanthanoid part of the magnetocaloric cooler serves at the same time as a «cold» section of the nozzle of the combined regenerator, which increases the efficiency of regeneration. The design sketch of the MCS cooler is illustrated in the figure.
The isothermal expansion in the new design of the Stirling cycle is performed by the expander piston (10) when moving to the right (see figure). At the same time, helium gas, which is the working gas of the cycle, expands, and, upon working, it cools, taking heat from the cooled object (6).
Cooling capacity in an ideal cycle is estimated by the equation:
Qо = М R Tо ln (V1 / V2), (1)
where M is the mass flow rate of helium, measured in kg / s; R is the gas constant of helium, J / (kg · K), T0 is the cryostatting temperature, measured in degrees K; V1, V2 are the maximum and minimum cycle volumes, respectively, measured in cubic meters.
Isochoric cooling is carried out in a regenerator which has two areas (nozzles): the main one, made of steel 12X18H10T (5), and paramagnetic (lanthanoid), made of fine-grained polycrystalline holmium (9). The combined regenerator designed in this way with a 20% filling along the length of holmium from the side of the cryostatting zone has high thermal conductivity in the temperature range 60–80 K. This constructive solution will allow for more efficient regeneration of the working gas (helium). The efficiency of regeneration is determined by the losses from under-regeneration of the regenerator:
where Mh, Mn is the mass of helium and nozzle of the regenerator, respectively, kg; crh, cn is the heat capacity of helium and the nozzle of the regenerator, respectively, J / (kg · K), Th, Tc, respectively, are the temperatures of the «hot» and «cold» blast, K.
The average specific heat capacity of 12XH10T steel used in previous developments [utility model patent No. 142459] in the temperature range 60–80 K is about 150 J / (kg K). At the same time, in pure holmium in this temperature range, the specific heat is about 220 J / (kg · K). Therefore, the losses from under-recovery when replacing in the cryostatting zone of the regenerator nozzle section from 12X18H10T (5) to holmium (9) should decrease by 25–30%, ceteris paribus. The efficiency of the microcryogenic system will increase by 10–15%.
The second cooling stage in the Stirling microcryogenic system, magnetocaloric, includes the paramagnetic holmium part of the regenerative heat exchanger (9) and the ring active magnetic element (8).
The operation of the second stage of cryostatting is implemented as follows. The expander piston (10), in the extreme left position, is located concentrically in the annular active magnetic element (8) before the first phase of cryostatting is implemented. In this case, the paramagnetic part of the regenerative heat exchanger is under the influence of a magnetic field with a strength of 2 T. Holmium is isothermally magnetized. The heat of magnetization is removed during operation of the device. Then, in the process of expansion, movement of the expander piston to the right and subsequent cooling of helium, the holmium part of the regenerator (9) moves from the field of action of the magnet (8). The adiabatic demagnetization process is performed with decreasing holmium temperature, which is described by the expression for the cooling capacity with the magnetocaloric effect :
where M is the magnetization of holmium, A / m; T is the temperature, K; N is the magnetic field strength, T.
Both cryostatting stages work synchronously in time. When the microcryogenic system reaches the mode, the displacement frequency of the expander piston (10) decreases, which makes it possible to effectively implement the MC effect, since the MC effect cannot be obtained at high frequencies due to the presence of magnetic hysteresis of the active magnet (8). The second stage of cryostatting will lower the cryostat temperature to 60–65 K.
An intermetallic rare-earth material, neodymium-iron-boron is used as the material of the active magnet. The «cold» area of the regenerator is made of high-purity paramagnetic polycrystalline holmium with a fine-grained structure. The main area of the regenerator nozzle is made in the form of mesh elements made of 12X18H10T stainless steel [9–11].
The proposed Stirling cooling device with a magnetocaloric cryostatting stage will expand the range of cryostatting temperatures to 80–60 K, increase the efficiency of the microcryogenic system by 10–15%, and reduce power consumption by 15%.
The researches have shown that the developed design ensures the execution of a technical solution. In the active regenerator, effective heat recovery is achieved, and additional cooling is created in the second magnetocaloric stage of the microcryogenic system.
Thus, the constructive solution provides a reduction in cryostatting temperature to 60K, while the power consumption is reduced by 12–15% compared with the known technical solutions, and the efficiency of the device is increased by 8–10%.
A two-stage microcryogenic system for photodetector module cryostatting based on a gas cryogenic Stirling machine with a final cooling stage based on the magnetocaloric effect has been developed. The working fluid of the first stage is helium gas, the working fluid of the second stage is a two-functional effective active regenerative heat exchanger for pre-cooling, made in the «cold» area of rare-earth metal, holmium. In the first stage, the process of helium isothermal expansion with heat is introduced according to the traditional Stirling cycle, in the second stage, the cooled helium is finally cooled in the process of removing the magnetic field from the magnetocaloric stage (the rare-earth part of the regenerative heat exchanger), thus, the magnetocaloric effect is implemented. Thus, after the final cooling, helium is able to bring the cryostatting temperature of the object to a temperature of near 60K, while maintaining sufficient energy efficiency of the cycle.
An application for an invention has been filed for the construction of the MCS with the Federal Institute of Industrial Property (FIIP).
Andreenko A. S., Belov K. P., Nikitin S. A., Tishin A. M. Magnitokaloricheskie effekty v redkozemel’nyh magnetikah. Uspekhi fizicheskih nauk. 1989; 158(4): 597.
Tarasov V. V., Yakushenkov Yu. G. Infrakrasnye sistemy «smotryashchego» tipa. – M.: “Logos”. 2004.
Formozov B. N. Aerokosmicheskie fotopriemnye ustrojstva v vidimom i infrakrasnom diapazonah. – S-Pb: SPbGUAP. 2002.
Politova G.A., Burhanov G.S, Tereshina I. S., Kaminska T. P., Chzhan V. B., Tereshina E. A. Vliyanie legirovaniya alyuminiem i zhelezom na strukturu, magnitnye i magnitokaloricheskie svojstva mnogokomponentnyh splavov Tb–Dy–Ho–Co. Zhurnal tekhnicheskoj fiziki. 2017; 87(4):4–5.
Samvelov A.V., Yasev S. G., Moskalenko A. S., Starcev V. V., Pahomov O. V. Integral’nye mikrokriogennye sistem Stirlinga v sostave kriostatiruemyh fotopriemnyh modulej na osnove matric dlinnovolnovoj IK‑oblasti. Photonics Russia. 2019;13(1):58–64.
Eremchuk A.I., Samvelov A. V. i dr. Optimizaciya davleniya rabochego gaza pri promyvke pered zapolneniem mikrokriogennyh sistem ohlazhdeniya MFPU. Uspekhi prikladnoj fiziki. 2013; 1(2): 224–226.
Arakelov G.A., Samvelov A. V. Voprosy optimizacii rezhimov elektropitaniya termoelektricheskih ohladitelej fotopriemnikov v sostave optiko-elektronnoj apparatury. Prikladnaya fizika. 2012; 6: 78–84.
Suslov A. D. Kriogennye gazovye mashiny. – M.: Mashinostroenie. 1982.
Nefed’ev S. P., Dema R. R., Molochkova O. S. Materialovedenie. – Magnitogorsk: Magnitogorsk state technical University named G. I. Nosov. 2014.
Kolesnikov A.M ., Samvelov A. V., Slovesnov K. V. Mikrokriogennye sistemy Stirlinga v integral’nom ispolnenii s povyshennym resursom raboty. Prikladnaya fizika. 2010; 2: 80–82.
Troshkin Yu. S., Chapkevich A. L., Gorbunov E. K., Posevin O. P., Samvelov A. V. Prikladnaya fizika.1999; (3): 60–65.
Андреенко А.С., Белов К. П., Никитин С. А., Тишин А. М. Магнитокалорические эффекты в редкоземельных магнетиках. Успехи физических наук. 1989; 158(4): 597.
Тарасов В.В., Якушенков Ю. Г. Инфракрасные системы «смотрящего» типа. – М.: «Логос». 2004.
Формозов Б. Н. Аэрокосмические фотоприемные устройства в видимом и инфракрасном диапазонах. – С-Пб: СПбГУАП. 2002.
Политова Г.А., Бурханов Г.С, Терешина И. С., Каминска Т. П., Чжан В. Б., Терешина Е. А. Влияние легирования алюминием и железом на структуру, магнитные и магнитокалорические свойства многокомпонентных сплавов Tb–Dy–Ho–Co. Журнал технической физики. 2017;87(4):4–5.
Самвелов А.В., Ясев С. Г., Москаленко А. С., Старцев В. В., Пахомов О. В. Интегральные микрокриогенные систем Стирлинга в составе криостатируемых фотоприемных модулей на основе матриц длинноволновой ИК‑области. Фотоника. 2019;13(1):58–64.
Еремчук А. И., Самвелов А. В. и др. Оптимизация давления рабочего газа при промывке перед заполнением микрокриогенных систем охлаждения МФПУ. Успехи прикладной физики. 2013; 1(2): 224–226.
Аракелов Г. А., Самвелов А. В. Вопросы оптимизации режимов электропитания термоэлектрических охладителей фотоприемников в составе оптико-электронной аппаратуры. Прикладная физика. 2012; 6: 78–84.
Суслов А. Д. Криогенные газовые машины. – М.: Машиностроение. 1982.
Нефедьев С. П., Дема Р. Р., Молочкова О. С. Материаловедение. – Магнитогорск: Магнитогорский государственный технический университет. им. Г. И. Носова. 2014.
Колесников А. М., Самвелов А. В., Словеснов К. В. Микрокриогенные системы Стирлинга в интегральном исполнении с повышенным ресурсом работы. Прикладная физика. 2010; 2: 80–82.
Трошкин Ю. С., Чапкевич А. Л., Горбунов Е. К., Посевин О. П., Самвелов А. В. Прикладная физика.1999 (3):60–65.