研究者業績
基本情報
- 所属
- 国立研究開発法人宇宙航空研究開発機構 宇宙科学研究所 特任助教
- 学位
- 博士（工学）(名古屋大学)
- 研究者番号
- 50866481
- J-GLOBAL ID
- 201701004920973937
- researchmap会員ID
- B000277091
- 外部リンク
経歴
6-
2021年7月 - 現在
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2021年1月 - 現在
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2021年1月 - 現在
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2019年4月 - 2020年12月
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2019年10月 - 2020年9月
学歴
3-
2016年4月 - 2019年3月
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2014年4月 - 2016年3月
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2010年4月 - 2014年3月
受賞
12-
2023年3月
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2020年5月
論文
23-
International Journal of Heat and Mass Transfer 221 125037-125037 2024年4月 査読有り
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Applied Thermal Engineering 121109-121109 2023年7月 査読有り筆頭著者責任著者
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Applied Thermal Engineering 219 119573-119573 2023年1月 査読有り
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Journal of Low Temperature Physics 211(5-6) 384-397 2022年12月2日 査読有りLiteBIRD is a future satellite mission designed to observe the polarization of the cosmic microwave background radiation in order to probe the inflationary universe. LiteBIRD is set to observe the sky using three telescopes with transition-edge sensor bolometers. In this work we estimated the LiteBIRD instrumental sensitivity using its current design. We estimated the detector noise due to the optical loadings using physical optics and ray-tracing simulations. The noise terms associated with thermal carrier and readout noise were modeled in the detector noise calculation. We calculated the observational sensitivities over fifteen bands designed for the LiteBIRD telescopes using assumed observation time efficiency.
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Progress of Theoretical and Experimental Physics 2023(4) 2022年11月21日 査読有りAbstract LiteBIRD the Lite (Light) satellite for the study of B-mode polarization and Inflation from cosmic background Radiation Detection, is a space mission for primordial cosmology and fundamental physics. The Japan Aerospace Exploration Agency (JAXA) selected LiteBIRD in May 2019 as a strategic large-class (L-class) mission, with an expected launch in the late 2020s using JAXA’s H3 rocket. LiteBIRD is planned to orbit the Sun-Earth Lagrangian point L2, where it will map the cosmic microwave background (CMB) polarization over the entire sky for three years, with three telescopes in 15 frequency bands between 34 and 448 GHz, to achieve an unprecedented total sensitivity of 2.2 μK-arcmin, with a typical angular resolution of 0.5○ at 100 GHz. The primary scientific objective of LiteBIRD is to search for the signal from cosmic inflation, either making a discovery or ruling out well-motivated inflationary models. The measurements of LiteBIRD will also provide us with insight into the quantum nature of gravity and other new physics beyond the standard models of particle physics and cosmology. We provide an overview of the LiteBIRD project, including scientific objectives, mission and system requirements, operation concept, spacecraft and payload module design, expected scientific outcomes, potential design extensions and synergies with other projects. Subject Index LiteBIRD cosmic inflation, cosmic microwave background, B-mode polarization, primordial gravitational waves, quantum gravity, space telescope
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International Journal of Heat and Mass Transfer 195 2022年10月 査読有りIn this study, the effects of an increased evaporation area known as the triple-phase contact line (TPCL), of the porous wick and improved evaporator wettability on the loop heat pipe (LHP) heat transfer performance were evaluated experimentally and theoretically. An infrared camera and a microscope were used to observe the thermo-fluid behavior of porous wicks with different vapor grooves widths and evaporator heating plates with different inner wall structures in the experiment. The porous wick's vapor groove widths were 1.0 mm, 0.5 mm, and 0.2 mm. A normal heating plate and a micro-grooved heating plate were used as the evaporator case. As a result, it was clarified that processing the micro-grooves on the heating plate improved the evaporative heat transfer coefficient and maximum heat flux, regardless of the vapor grooves width of the porous wick. Furthermore, it was proposed that both of them increased significantly as the vapor grooves width increased. The thermal-hydraulic numerical model that predicted the heat transfer coefficients for each case was developed. The calculation results showed a significant increase in the heat transfer coefficient as the TPCL appearance rate, which expresses how much the TPCL appears in the micro-grooves, increased, and this increasing tendency was in good agreement with the experimental results. Furthermore, it was proposed that the TPCL appearance rate at a high heat flux was reduced as the vapor grooves width decreased. The results indicate a new promising approach for improving the heat transfer performance of LHP evaporators.
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Journal of Low Temperature Physics 2022年9月5日 査読有りFeedhorn- and orthomode transducer- (OMT) coupled transition edge sensor (TES) bolometers have been designed and micro-fabricated to meet the optical specifications of the LiteBIRD high frequency telescope (HFT) focal plane. We discuss the design and optical characterization of two LiteBIRD HFT detector types: dual-polarization, dual-frequency-band pixels with 195/280 GHz and 235/337 GHz band centers. Results show well-matched passbands between orthogonal polarization channels and frequency centers within 3% of the design values. The optical efficiency of each frequency channel is conservatively reported to be within the range 0.64-0.72, determined from the response to a cryogenic, temperature-controlled thermal source. These values are in good agreement with expectations and either exceed or are within 10% of the values used in the LiteBIRD sensitivity forecast. Lastly, we report a measurement of loss in Nb/SiN x/Nb microstrip at 100 mK and over the frequency range 200-350 GHz, which is comparable to values previously reported in the literature.
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Journal of Cosmology and Astroparticle Physics 2022(4) 2022年4月 査読有りA methodology to provide the polarization angle requirements for different sets of detectors, at a given frequency of a CMB polarization experiment, is presented. The uncertainties in the polarization angle of each detector set are related to a given bias on the tensor-to-scalar ratio r parameter. The approach is grounded in using a linear combination of the detector sets to obtain the CMB polarization signal. In addition, assuming that the uncertainties on the polarization angle are in the small angle limit (lower than a few degrees), it is possible to derive analytic expressions to establish the requirements. The methodology also accounts for possible correlations among detectors, that may originate from the optics, wafers, etc. The approach is applied to the LiteBIRD space mission. We show that, for the most restrictive case (i.e., full correlation of the polarization angle systematics among detector sets), the requirements on the polarization angle uncertainties are of around 1 arcmin at the most sensitive frequency bands (i.e., ≈ 150 GHz) and of few tens of arcmin at the lowest (i.e., ≈ 40 GHz) and highest (i.e., ≈ 400 GHz) observational bands. Conversely, for the least restrictive case (i.e., no correlation of the polarization angle systematics among detector sets), the requirements are ≈ 5 times less restrictive than for the previous scenario. At the global and the telescope levels, polarization angle knowledge of a few arcmins is sufficient for correlated global systematic errors and can be relaxed by a factor of two for fully uncorrelated errors in detector polarization angle. The reported uncertainty levels are needed in order to have the bias on r due to systematics below the limit established by the LiteBIRD collaboration.
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Proceedings of SPIE - The International Society for Optical Engineering 12180 2022年LiteBIRD is a JAXA-led international project that aims to test representative inflationary models by performing an all-sky cosmic microwave background radiation (CMB) polarization survey for 3 years at the Sun-Earth Lagrangian point L2. We aim to launch LiteBIRD in the late 2020s. The payload module (PLM) is mainly composed of the Low-Frequency Telescope (LFT), the Mid-Frequency Telescope and High-Frequency Telescope (MHFT), and a cryo-structure. To conduct the high-precision and high-sensitivity CMB observations, it is required to cool the telescopes down to less than 5 K and the detectors down to 100 mK. The high temperature stability is also an important design factor. It is essential to design and analyze the cryogenic thermal system for PLM. In this study, the heat balance, temperature distribution, and temperature stability of the PLM for the baseline design are evaluated by developing the transient thermal model. The effect of the Joule-Thomson (JT) coolers cold tip temperature variation, the periodical changes in subK Adiabatic Demagnetization Refrigerator (ADR) heat dissipation, and the satellite spin that generates the variable direction of solar flux incident are implemented in the model. The effect of contact thermal conductance in the LFT and the emissivity of the V-groove on the temperature distribution and heat balance are investigated. Based on the thermal analysis, it was confirmed that the PLM baseline design meets the requirement of the temperature and the cooling capability of the 4K-JT cooler. In addition, the temperatures of the V-groove and the LFT 5-K frame are sufficiently stable for the observation. The temperature stability of the Low Frequency Focal Plane (LF-FP) is also discussed in this paper.
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Proceedings of SPIE - The International Society for Optical Engineering 12180 2022年LiteBIRD is a spacecraft to observe the polarization signal of the cosmic microwave background radiation (CMB). In the development of its payload module, it is important to design the mechanical structures with enough rigidity to withstand the launch environment while providing enough thermal insulation to cool the telescopes down to 5 K. We need to reduce the mass of the 5-K structure, which consists of three telescopes, the low-frequency telescope (LFT) led by JAXA and the mid-frequency and high-frequency telescopes (MFT and HFT) led by CNES. In this paper, we report the mechanical design of the LFT and the structural analysis using Nastran. We made a structural mathematical model of the LFT and performed modal and quasi-static analyses. We successfully reduced the LFT mass while keeping the natural resonance frequency higher than requirements. Additionally, we report the mechanical design and the current status of the structural analysis for the payload module.
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APPLIED THERMAL ENGINEERING 195 2021年8月 査読有り筆頭著者This paper presents a three-dimensional heat transfer analysis of a flat-plate oscillating heat pipe (OHP). To enhance implementation of OHPs in various applications, it is important to understand the comprehensive phenomena that include thermal diffusion in the whole structure and thermal hydraulics in the channel. We developed an OHP model that includes the effect of thermal diffusion and thermo-fluid behavior. The model was validated with experimental results of a flat-plate aluminum OHP which has a size of 200 mm x 90 mm x 3.8 mm, a channel diameter of 1.0 mm, and a turn number of 42. The effect of surface roughness in the channel and liquid film thickness on operating temperature is investigated. The relation between thermo-fluid behavior in the channel and temperature distribution of the OHP is analyzed. For aluminum OHP, the temperature difference across the thickness direction is 0.1 ?C which is relatively small, whereas, the moving hot spot: local hightemperature region, is found in the planer surface. The maximum hot spot superheat temperature reached 5.4 ?C for 200 W. The novelties of this paper are to develop the three-dimensional comprehensive OHP model and to reveal the combined effect of thermo-hydraulic phenomena and thermal diffusion in OHP structure.
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International Journal of Multiphase Flow 140 2021年7月 査読有り筆頭著者責任著者This paper presents a thermo-fluid dynamic analysis in a micro-textured evaporator for loop heat pipes (LHPs) that has a super wetting surface with ethanol on the basis of an experiment and modeling. In the experiment, three kinds of stainless steel plates with various morphologies of heat transfer surfaces were tested: a normal flat plate, a sandblasted plate, and a micro-groove plate. The measured contact angles between the surfaces and ethanol were 8.2° ± 1.3°, 0°, and 0°, respectively. Evaluation of the heat transfer performance and liquid-vapor interface behavior was conducted using microscale infrared and visible observations. As a result, it was revealed that the sandblasted plate and the micro-groove plate showed 7 times and 20 times higher heat transfer coefficient under high heat flux conditions respectively, compared with the normal flat plate. Different liquid-vapor interface behaviors were found between the plate types. In the modeling, the heat transfer coefficient was predicted for each case. It was found that nucleate boiling heat transfer induced by rough surface increased the heat transfer performance in the case of the sandblasted plate. In addition, it was revealed that the thin film evaporation at the long triple-phase contact line significantly enhanced heat transfer performance in the case of the micro-groove plate. The findings indicate a new promising approach to enhance the heat transfer coefficient of LHP evaporators.
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JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH 2020年11月 査読有りThe water wettability of porous stainless steel specimens was enhanced via a nanoscaled silica coating for application to passive two-phase heat transfer devices. A combination of porous stainless steel and water has attracted attention in the area of the heat transfer devices. However, the water wettability of stainless steel is poor, limiting the performance of the devices. In the present study, the silica coating of the specimens was conducted via a reaction of tetraethyl orthosilicate (TEOS) after pretreatment using NaOH aq. or HCl aq. Energy-dispersive X-ray spectrometry revealed that the amount of silica deposited on the surface was dependent on the pretreatment conditions and the composition of the silica-coating solutions. Measurement of porous properties indicated that the silica coating did not affect pore diameter and gas permeability since the coating was in nanoscale. Microscale contact angles were directly evaluated using an environmental SEM. The specimens showed excellent water wettability when they were covered with numerous tiny silica bumps. When the specimen was pretreated with 2 M NaOH aq. and coated in weak alkaline TEOS solution, the contact angle of the porous stainless steel decreased from 87 degrees to 54 degrees after silica coating. The excellent water wettability originated from the relatively smooth surface and a sufficient coverage ratio, which resulted from the moderate strength of chemical etching of the NaOH aq. and the mild silica-coating condition in the weak alkaline solution.
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International Journal of Heat and Mass Transfer 158 119964-119964 2020年9月 査読有り筆頭著者責任著者This paper presents an effect of reservoir location on heat transfer characteristics of a capillary pumped loop (CPL). The designed CPL has a cylindrical evaporator with a diameter of 12 mm and a length of 65 mm. A stainless steel porous medium that has a pore radius of 4.4 mu m is used as a wick. Heat transport length is designed as 1000 mm. The experiments were conducted with four types of reservoir location such as (1) Distance from the evaporator, L = 150 mm, (2) L = 250 mm, (3) L = 750 mm, (4) L = 1450 mm. As results, it was found that the CPL of case (1) showed high operating temperature and much smaller heat transfer capability such as 10 W. For cases of (2) - (4), the maximum heat transfer capability reached 140 - 160 W and showed the good controllability of the operating temperatures ranging from 60 to 100 degrees C. The reason for the low heat transfer performance of case (1) and the difference in operational characteristics are discussed. It was found that there is a design limitation of the reservoir location of CPLs. In addition, the operation of the CPL that reservoir was located much far from the evaporator was successfully demonstrated. (C) 2020 Elsevier Ltd. All rights reserved.
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INTERNATIONAL JOURNAL OF THERMAL SCIENCES 140 530-538 2019年6月 査読有り
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APPLIED THERMAL ENGINEERING 153 828-836 2019年5月5日 査読有り
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International Journal of Heat and Mass Transfer 938-945 2019年3月1日 査読有り© 2018 In this study, the characteristic of liquid–vapor interface behavior in a capillary evaporator of loop heat pipes (LHPs) is studied experimentally and theoretically. The behavior of a phase–change heat transfer at the surface of a fine porous medium that is called a wick, is evaluated using microscopic infrared camera and microscope. Four distinct samples made using four different materials (polytetrafluoroethylene and stainless steel (SS1.0 μm, SS4.5 μm, SS22 μm)) were used to simulate a part of the wick used in the evaporator. The changes in a heat transfer coefficient were caused by three types of liquid–vapor interface behaviors. In the analysis, a one-dimensional model of the liquid–vapor interface behavior in the wick is proposed based on thin liquid film evaporation theory. The predicted heat transfer coefficient was in good agreement with the experimental data.
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SURFACE TOPOGRAPHY-METROLOGY AND PROPERTIES 5(4) 2017年12月 査読有りControl of thermally induced liquid-vapor interface behavior at the contact surface of porous media is crucial for development of two-phase heat transfer devices such as loop heat pipes. The behavior experiences three modes with increase of heat flux, and the middle mode possesses the highest heat transfer performance. In this paper, the effect of improving wettability of the porous media is demonstrated experimentally and numerically for the first time, in particular with regard to the effect on a domain of the middle mode. Ethanol wettability of a porous stainless steel was improved via a facile method, which was a simple acid treatment. As a result, the domain of the middle mode was extended as a consequence of the wettability improvement. The mode transfers from the middle to the last one when the pressure drop in the liquid supply exceeds the capillary pressure of liquid bridges formed between the heating plate and the porous medium. Hence, the extension of the domain suggested that the capillary pressure was increased by the wettability improvement. This was verified via numerical calculation. The calculated capillary pressure was increased by 7% after improving wettability, which resulted in the extension of the domain of the middle mode.
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Applied Thermal Engineering 2016年9月30日 査読有り© 2017 Elsevier Ltd.This paper reports on a visualization study investigating the characteristics of the liquid-vapor interface behavior on the surface of a wick in the capillary evaporator of loop heat pipes. Observations were conducted with a microscopic infrared camera and a microscope. Nine different samples simulate a part of a wick were made by two different materials: polytetrafluoroethylene (PTFE); and stainless steel (SS). First, three types of liquid-vapor interface behavior are reported. They are (a) evaporation at the menisci that formed at the boundary line between the heating plate, wick, and groove, (b) evaporation at the surface of small liquid bridges through nucleate boiling at the contact surface between the heating plate and wick, and (c) evaporation at the menisci in the wick. Secondly, the effect of the groove width on the maximum heat flux and the depth of a vapor pocket in the wick are reported. It was found that, as the groove width reduced, a higher heat transfer capacity was observed in both of the materials, except in the wick that had the smallest groove width. Additionally, it was found that the wick with the smallest fin width had the greatest potential for preventing vapor pockets formation in the wick.
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APPLIED THERMAL ENGINEERING 107 167-174 2016年8月 査読有りThis paper reports the test results and evaluation of gravity effects on long-distance loop heat pipe (LLHP) with 10 m distances for heat transport. First, the LLHP was designed based on the one-dimensional steady-state model, fabricated and tested. Test results showed the LLHP could transport heat up to 340 W for 10 m and the thermal resistance between the evaporator and the condenser was 0.12 K/W under horizontal condition. Next, the LLHP was tested in top-heat mode. The maximum heat transports were 310, 270, 220 W and the thermal resistances were 0.15, 0.17, 0.22 K/M under 30, 60, 100 cm antigravity condition respectively. The heat transfer efficiency of the LLHP was discussed in detail. The evaluation results showed 71.4% of the 340 W heat load was dissipated at the condenser under the horizontal condition. On the other hand, 62.8, 61.8, 57.1% of the maximum heat load was dissipated at the condenser under 30, 60, 100 cm anti-gravity condition respectively. The calculation model was in good agreement with the experimental results by considering the existence of a vapor pocket between the evaporator case and the vapor-liquid interface. This analysis indicated the vapor blanket generates easily and becomes thicker as anti-gravity effect increases. (C) 2016 Elsevier Ltd. All rights reserved.
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Journal of Electronics Cooling and Thermal Control 6(2) 33-41 2016年 査読有り
MISC
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共同利用・共同研究拠点「流体科学国際研究教育拠点」活動報告書 = Activity report Joint Usage/Research Center "Fluid Science Global Research and Education Hub" 141-143 2022年
講演・口頭発表等
110-
20th International Conference on Flow Dynamics 2023年11月
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20th International Conference on Flow Dynamics 2023年11月
担当経験のある科目(授業)
2-
2021年9月 - 現在
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2022年9月航空宇宙流体工学特論(分担) (東北大学)
所属学協会
5共同研究・競争的資金等の研究課題
7-
日本学術振興会 科学研究費補助金 若手研究 2023年4月 - 2026年3月
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日本学術振興会 科学研究費補助金 基盤研究(B) 2023年4月 - 2026年3月
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東北大学流体科学研究所 公募共同研究 2021年4月 - 2024年3月
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文部科学省卓越研究員事業 令和2年度卓越研究員研究費 2021年1月 - 2022年3月
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日本学術振興会 科学研究費補助金 若手研究 2020年4月 - 2022年3月
