Browsing by Author "Bloem, Edwin"
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Item Embedded Pulsating Heat Pipe for Improved Heat Spreading in CFRP Equipment Panels for Satellites(2023 International Conference on Environmental Systems, 2023-07-16) van Es, Johannes; Benthem, Roel; Bloem, Edwin; Klomp, Ronald; Vliet, Adry Van; Sieber, GunnarTo avoid hot spots on satellites for equipment mounted on Carbon Fibre Reinforced Polymer (CFRP) panels, there is an increasing demand for improved heat spreading. A technology investigated in this paper is embedding a Pulsating Heat Pipe inside a CFRP sandwich panel. A PHP is a meandering tube partly filled with Ammonia effectively achieving an enhanced conductive value above 10,000 W/m/K along the length of the tubing. Although the physics behind the operation of a PHP is not yet fully understood, it can be constructed based on experimental experience available at the Netherlands Aerospace Centre. The paper describes the design, performance analysis, and manufacturing process of an Engineering Model (EM) of a 0.8 m2 PHP panel. It concludes with performance tests done in a representative environment, achieving TRL 4 to 5. The EM panel has PAN based HT carbon fibre composite face sheets, a carbon foam layer with an embedded pulsating heat pipe tube supported by an aluminium honeycomb. The test programme included leak testing, proof pressure testing, pressure cycle testing, burn-in testing, performance testing in various orientations, and thermal tests in vacuum. In ambient conditions the PHP performed according to expectations with a heat spreading capability > 300 W/m2. However in vacuum the PHP did not operate at all. This unexpected failure is presented including the root cause investigation. The paper ends with an outlook on further research and potential applications. Proposed paper sections: 1. Background info on PHP panel 2. Panel design process 3. Panel manufacturing process description 4. PHP EM panel and test set-up 5. Test results summary 6. TV test anomaly and root cause investigation 7. Summary & recommendationsItem Spacecraft Harness Evaluator (SHARE) a New Software Tool for Thermal Analysis of Spacecraft Harnesses(51st International Conference on Environmental Systems, 7/10/2022) Bloem, Edwin; van Benthem, Roel; van Es, Johannes; Kroll, RobertHarness sizing for space applications is driven by derating rules. The respective derating standards are known to be rather conservative, resulting in significant design margins and thus unnecessarily increasing harness mass. A recent ESA study, conducted by the Royal Netherlands Aerospace Centre (NLR) and Airbus DS (France), aimed at reassessing existing derating rules, supported by extensive testing and analysis, and ultimately led to an update of the ECSS-Q-ST-30-11C standard to Rev2, relevant for a wide range of European space projects. The update resulted in a significant reduction of the uncertainty margins and encourages the use of validated thermal simulation tools to further optimize harness designs. As of today, no such simulation tool, specifically validated for harnesses in space applications is commercially available to the European space industry. This paper describes the validation of the Spacecraft HARness Evaluator (SHARE), a new tool that performs thermal analysis and enables mass optimization of spacecraft harnesses. The validation of SHARE and its underlying thermal model is performed via correlation and verification using an extensive set of measurement data, consisting of 417 single wire and 117 cable bundle test cases, collected during thermal-vacuum testing in the frame of the before mentioned ESA study. The correlation is performed by means of Black-Box optimization to determine �optimal values�, for the emissivity, the bundle-to-enclosure radiative scaling factor and the wire-to-wire contact conductance. It is concluded, that SHARE is able to predict the maximum temperature in a given wire bundle in the defined validation range with an accuracy of -9.5�C / +9.8�C in 95% of all cases. It is foreseen to further improve SHARE by enhancing the accuracy and the validation range through model extensions and additional thermal test campaigns. Future updates of SHARE may include shielding, solar flux consideration and convective analysis in various atmospheres, covering planetary exploration.Item Thermal Analysis and Verification of CubeSat Designs with ESATAN-TMS(50th International Conference on Environmental Systems, 7/12/2021) te Nijenhuis, Arne; Brouwer, Hugo; Jonsson, Martin; Bloem, Edwin; van Donk, Gerrit; Lamers, Bram; Pauw, Aswin; van Benthem, RoelFor the competitive CubeSat market the importance of thermal analysis is often underestimated, which can lead to temperature critical designs. Clearly, with the trend of increasing power density for CubeSats, thermal design deserves more attention. To anticipate on this trend, a joint effort of ISIS - Innovative Solutions in Space and NLR - Royal Netherlands Aerospace Centre was initiated to prepare a framework for modular thermal analysis of CubeSats designs using ESATAN-TMS. In order to increase the accuracy of the initial model parameters used during the verification process, dedicated tests were conducted on specific thermal properties of CubeSats, in order to both verify and supplement literature values. These tests were primarily focused on thermal properties of PCBs, which play a prominent role in the thermal control of CubeSats. Additionally, conductive interfaces of 2U CubeSat assemblies were tested in a thermal vacuum chamber at NLR, and the results were used in the correlation with thermal models. The correlation approach used a black box optimization method for improved fitting of the CubeSat model parameters. In this process the RMS error of the temperature predictions of the CubeSat model is minimised by automatically adjusting a set of pre-defined correlation parameters, amongst which are contact conductance, the thermal conductivity of PCBs and radiative properties, within a pre-defined correlation interval. The verification process as discussed in this paper is the starting point for the creation of a library of validated submodels in ESATAN-TMS which can be used for thermal designs of CubeSats in the future.