Browsing by Author "van Es, Johannes"
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Item Accumulator testing in multiple on-ground orientations for a small Mechanically Pumped Two-phase Loop (MPTL) for CCD thermal control(50th International Conference on Environmental Systems, 7/12/2021) van Es, Johannes; Pauw, Aswin; Van Vliet, Adry; Meng, Qingliang; Zhen Ming, Zhao; van Gerner, Henk JanNLR designed and developed on request and in co-operation with BISME an Engineering Model of a Mechanically Pumped Two-phase Fluid Loop (MPTL) Thermal Control System for CCD thermal control. The objective is to provide accurate thermal control (�1 �C) and a temperature uniformity of <2 �C for nine CCD cameras. The accumulator is a crucial component of such a two-phase pumped thermal control system which allows for loop density changes, and controls the pressure and thereby temperature of the thermal control system. As the accumulator is a large volume with both vapour and liquid, the accumulator is specially designed with internal wick structures for operation in micro-gravity to assure liquid is located at the accumulator inlet and below the accumulator heaters. The design is made such that operation in multiple on-ground orientations is possible. This is demonstrated by tests. The paper starts with a brief overview of the MPTL project and the MPTL design. Subsequently the MPTL accumulator design and the test set-up are explained and test results in various orientations are presented. The paper concludes with an outlook on future MPTL developments and applications.Item Breadboard Testing of a HiPeR Inflatable Radiator (HiPeR INFRA)(49th International Conference on Environmental Systems, 2019-07-07) de Groot, Tom; Schwieters, Boudewijn; van Benthem, Roel; van Es, Johannes; Pauw, AswinWith a twenty times higher thermal conductivity per unit mass than aluminium, pyrolytic graphite (PG) offers great potential in the application to spacecraft thermal control systems. Over the last years, Airbus Defence and Space Netherlands (Airbus DS NL) has been developing thermal control applications for this material. The patented High Performance Radiator (HiPeR) uses the PG to efficiently spread the heat from a heat source over a large radiative area. Recently, Airbus DS NL and the Royal Netherlands Aerospace Centre (NLR) have been working on a HiPeR Inflatable Radiator (INFRA) application. This concept consists of a HiPeR radiator and a single phase fluid loop. Flexible tubing enables the radiator to be rolled up to a small stowed volume. Once in orbit, the system pressure is increased, triggering the radiator to unroll and maintain its shape over the mission lifetime. Heat is supplied via the same fluid tube that gives the radiator its shape, making use of a dedicated mini-pump. To validate the functional design, a breadboard model has been made. Deployment and thermal performance have been tested successfully. Based on the measured data, the thermal performance of an INFRA system operating at a 45 °C root temperature in a space environment with a sink temperature of -270 °C would be approximately 300-325 W/m2, corresponding to a radiator efficiency of approximately 60%. This performance is deemed to be competitive, especially considering the mass-to-power (expected <10 kg / kW after a design iteration) and small stowed volume of such a system. Additionally, a small-scale breadboard test of protection measures against micro-meteoroids and orbital debris (MMOD) has yielded promising results. The revised design includes MMOD shielding in the form of bi-stable metal strips with a resulting probability of no penetration of the kapton fluid tubing of 0,9 over a lifetime of 15 years.Item Component development in Europe for Mechanically Pumped Loop Systems (MPLs) for cooling applications in space(46th International Conference on Environmental Systems, 2016-07-10) Benthem, Roel; van Es, Johannes; Jan van Gerner, Henk; Lapensee, Stephane; Schwaller, DavidThe objective of this paper is to discuss the status and advances for application of one- or two-phase Mechanically Pumped Loop (MPLs) in scientific and commercial space cooling systems. It gives a general overview of the components available in Europe such as pumps (micro, mini, piezo, centrifugal, non-centrifugal), compressors , valves (active, passive) , accumulators (with bellows, 2 phase or flow through) , pressure transducers, heat exchangers and deployable/light weight radiators. Potential applications are discussed as well as guidelines for performance analysis and fluid selection.Item Development and Testing of a Two-Phase Mechanically Pumped Loop for Active Antennae(2023 International Conference on Environmental Systems, 2023-07-16) van Gerner, Henk Jan; Kunst, Romaine; van den Berg, T.H; van Es, Johannes; Tailliez, Anne; Walker, Andy; Ortega, Cristina; Iriarte, Mónica; Roldan, Nuria; Ortega Castañeda, Christian; Castro, CharltonThe satellite telecommunications industry is currently undergoing significant evolutions. Future communication satellites need to accommodate a rapidly growing demand in data transfer, combined with more flexibility. For example, there is a strong need for Very High Throughput Satellites capable of delivering up to Tb/s over wide coverage areas. This is only possible when an active phased array antenna is used. However, cooling of active antennas requires the use of a highly efficient thermal control system because it has many heat sources (from hundreds to several thousands), high local heat fluxes (20 W/cm² at evaporator interface), high overall dissipation (around 10 kW), and isothermal requirements on the amplifier chain. These conditions are very difficult to meet with current thermal control solutions (e.g. heat pipes or loop heat pipes), but require a two-phase mechanically pumped fluid loop (MPL). In a MPL, a pump circulates a fluid which evaporates when it absorbs the waste heat from the active antenna. In the IMPACTA project, a demonstrator for such a MPL is being designed and build. This paper describes the test results for the IMPACTA demonstrator. The demonstrator is able to cool a total heat load of 9.8 kW divided over 10 parallel branches with a better than 2°C spatial temperature uniformity over the heat sources. In an active antenna application, the heat load can be unevenly distributed over the different branches. Tests show that even in the extreme case when half of the branches are turned off and the other half are set to full power, no sign of dry-out or too high temperatures is observed, demonstrating the ability of the MPL to cool imbalanced payloads. The demonstrator was tested in 3 different orientations and the test results are similar for all orientations, indicating that the system is not sensitive to gravity effects.Item Development of a miniature heat exchanger for mechanically pumped loop systems for active thermal control of CubeSats(51st International Conference on Environmental Systems, 7/10/2022) Ganzeboom, Thomas; van Es, Johannes; Formisani, LudovicaThe relatively high power density of CubeSats results in large amounts of heat generated that needs to be dissipated to prevent overheating of a satellite's components. At present, passive thermal control means are used to resolve CubeSats thermal issues, however, as these satellites evolve, advanced active Thermal Control Systems (TCS) will be required. Especially the novel CubeSat propulsion systems require dedicated TCS for the propulsion unit and the corresponding electronics. A promising type of TCS for CubeSats was determined to be the Mini-Mechanically Pumped fluid Loop (Mini-MPL). One such system has been developed at the Royal Netherlands Aerospace Centre (NLR), which consists of a single phase fluid loop that is used for component cooling. One of the important components of this system is the I/F with the Payload. For this purpose a Miniature Payload Heat Exchanger (MPHX) is developed as commercially available heat exchangers are typically impractical for use in space environments. A custom design for the MPHX is presented in this paper. During the design phase, a tool which is able to evaluate the cooling performance of different MPHX models has been built. Using this tool, the three best designs in terms of cooling performance have been identified: the offset strip fin heat exchanger, and two straight channels configurations with respectively triangular and trapezoidal cross sections. The design thermal resistance of the MPHX is in the order of 0.45 K/W with a liquid pressure drop in the order of 1 mbar. The heat exchangers are produced through additive manufacturing (using the Direct Metal Laser Melting method) which allows for greater flexibility and customization of the designs. The models are tested in a pumped fluid loop at the NLR's Thermal Management Facilities to confirm the results predicted in the design phase as well as feasibility of the DMLM fabrication method.Item Development of an Innovative Diaphragm Pump and Two-Phase Mechanically Pumped Loop for Active Antennas(51st International Conference on Environmental Systems, 7/10/2022) Castro, Charlton; Ortega, Christian; Picton, Kevin; Iriarte, Monica; Ortega, Cristina; van Gerner, Henk Jan; van den Berg, Ramon; van Es, JohannesThe development of Active Phased Array Antennas (APAAs) is a key enabler to effectively accommodate the growing demand of data transfer in commercial telecommunication satellites. A highly efficient and integrated thermal management system is required so as to reject the waste heat produced by the antenna�s Solid State Power Amplifiers (SSPAs). The development of such a thermal control system presents a number of technical challenges, chief among them being the large number of heat sources involved (typically ranging from 100 to 1000, with varying duty cycles), the need for spatial and temporal isothermal conditions across the set of SSPAs, as well as a low thermal gradient between the SSPAs and the working fluid, high total heat dissipation (10+ kW), high heat flux (20+ W/cm^2 at the evaporator�s interface) and large distances between the radiator and the payload, among others. An international consortium led by AVS is currently developing an ammonia two-phase pumped loop for APAAs within the frame of the IMPACTA project. MPLs (two-phase pumped loops in particular) are remarkably well suited for applications involving large heat loads, transfer of thermal energy over large distances (e.g. distributed payloads), high heat fluxes and payloads with tight temperature stability requirements. In addition, a novel positive displacement pump for spacecraft thermal control is being developed by AVS. The pump features a diaphragm architecture, piezoelectric actuator and passive check valves. A series of performance characterization tests of the EM have been conducted using a two-phase mechanically pumped loop test system in laboratory conditions. It is the purpose of the present paper to provide an overview of the IMPACTA project, current status and goals, as well as a description of the PDPump project, outlining the design and main requirements, as well as the development history and current status.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 Lightweight Two-Phase Pumped Cooling System with Aluminium Components produced with Additive Manufacturing(49th International Conference on Environmental Systems, 2019-07-07) van Gerner, Henk Jan; de Smit, Marc; van Es, Johannes; Migneau, MaximeThe amount of waste heat that is generated in electronic components in aerospace application is increasing because of higher electrical power demands. As a result, conventional cooling methods are not able to maintain the electronic component below its maximum temperature. For this reason, a two-phase Mechanically Pumped Fluid Loop has been developed for high-power electronic components in a commercial aerospace application. These electronic components generate a waste heat of 1200 W that is divided over several hotspots while the temperature gradient over the component has to be kept to a minimum. The developed cooling system uses R245fa as refrigerant and is made from aluminum components produced with additive manufacturing. The use of this novel production technique results in an unprecedented low system mass (2.5 kg) and small system dimensions. Measurements show that the system has an excellent thermal performance and is able to cool 2400W.Item Mini Mechanically Pumped Loop Modelling, Design and Tests for standardized cubesat thermal control(50th International Conference on Environmental Systems, 7/12/2021) van Es, Johannes; Ganzeboom, Thomas; van den Berg, T. H.; Van Vliet, Adry; Brouwer, Hugo S. B.; Elvik, SanderWith the miniaturization of space-borne sensors, more powerful payloads are anticipated to be used in small satellites. Therefore, new thermal concepts are required to cope with the increasing thermal dissipation and the negative effects. This paper presents a new thermal control concept to thermally standardize small satellites with power dissipation problems and making them thermally independent of their orbits. This new thermal design concept is a small Mechanically Pumped Loop (MPL). The heart of the system is the multi-parallel micro-pump (MPMP) as developed by the Netherlands Aerospace Centre (NLR). This pump concept provides a low mass MPL solution with high reliability. The article describes the concept of the loop and the pump in detail and explains how the design of the MPL takes into account the requirements imposed by CubeSats and their subsystems, thereby ensuring its compatibility with small satellites and a variety of missions. The Mini-MPL is modelled in Matlab to support MPL system design trade-offs. This model is described and modelling results are presented. Subsequently MPL tests results with a mini-MPL prototype are presented and compared with the model results to validate the model. The prototype tests demonstrate the mini-MPL performance and robust operation. Finally, the advantages and drawbacks of the system are elucidated by comparison with conventional thermal design options. The paper concludes with an outlook on further development and mini-MPL applications.Item Preliminary design of a mechanically pumped cooling system for active antennae(50th International Conference on Environmental Systems, 7/12/2021) Jan van Gerner, Henk; van den Berg, Ramon; van Es, Johannes; Tailliez, Anne; Walker, Andy; Ortega, Cristina; Iriarte, M�nica; Castro, CharltonThe satellite telecommunications industry is currently undergoing significant evolutions. Future communication satellites need to accommodate a rapidly growing demand in data transfer, combined with more flexibility. For example, there is a strong need for Very High Throughput Satellites capable of delivering up to Tb/s over wide coverage areas and an active phased array antenna is a powerful enabler to achieve that. However, cooling of active antennas requires the use of a highly efficient thermal control system because it has many heat sources (hundred or more), high local heat fluxes (20W/cm� at evaporator interface), high overall dissipation (around 10 kW), and isothermal requirements on the amplifier chain. These conditions are very difficult to solve with current thermal control solutions (e.g. heat pipes or loop heat pipes), but require a two-phase mechanically pumped fluid loop (MPL). In a MPL, a pump circulates a fluid which evaporates when it absorbs the waste heat from the active antenna. In the EU funded IMPACTA project, a demonstrator for such a MPL is being designed and built. This paper describes the preliminary design for this demonstrator, including the fluid selection and tests on evaporator samples.Item 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 Testing of high heat flux 3D printed aluminium evaporators(48th International Conference on Environmental Systems, 2018-07-08) van Gerner, Henk Jan; de Smit, Marc; van Helvoort, Darron; van Es, JohannesThe amount of waste heat that is generated in electronic components in aerospace application is increasing because of higher electrical power demands. As a result, conventional cooling methods are not able to maintain the electronic component below its maximum temperature. For this reason, a two-phase Mechanically Pumped Fluid Loop is being developed for high-power electronic components in a commercial aerospace application. These electronic components generate a heat load of 722 W on a 3.8 cm x 3.8 cm surface, resulting in a heat flux of 50 W/cm2. Tests with 8 different evaporator samples were carried out to determine the heat transfer coefficients and pressure drop and to select the optimal evaporator sample that is further developed in the detail design phase of the project. The tests show that the 3D printed aluminium evaporators are able to keep the heat source well below its maximum temperature.Item Transient Modelling of Pumped Two-Phase Cooling Systems: Comparison Between Experiment and Simulation with R134a(47th International Conference on Environmental Systems, 2017-07-16) van Gerner, Henk Jan; Bolder, Robin; van Es, JohannesTwo-phase pumped cooling systems are applied when it is required to maintain a very stable temperature in a system, for example in the AMS02, which was launched with a space shuttle (in May 2011) and subsequently mounted on the International Space Station. However, a two-phase pumped cooling system can show complex transient behavior in response to heat load variations. For example, when the heat load is increased, a large volume of vapor is suddenly created, which results in a liquid flow into the accumulator and an increase in the pressure drop. This will result in variations in the temperature in the system, which are undesired. It is necessary to calculate these temperature variations before an application is being built. For this reason, a software tool for transient two-phase systems has been developed by NLR. This tool numerically solves the one-dimensional time-dependent compressible Navier-Stokes equations, and includes the thermal inertia of all the components. In this paper, the numerical results from the model are compared to experimental results obtained with the NLR two-phase test facility with R134a as refrigerant.