Browsing by Author "Walker, Andy"
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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 an Engineering Model of a monophasic Electro Hydro Dynamic (EHD) pumped fluid loop within the frame of the NEOSAT pre-development activities(46th International Conference on Environmental Systems, 2016-07-10) Thorslund, Robert; Bjorneklett, Are; Antelius, Mikael; Tjiptahardja, Tisna; Huens, Thomas; Scommegna, Arnaud; Walker, AndyThis publication presents the development of a novel pumped fluid loop thermal regulation system, completely free of moving parts. This technology is using electro hydro dynamic pumping of a dielectric coolant. This pumping mechanism gives unique advantages, e.g. regulated thermal conductivity and high reliability. In the framework of ESA “NEOSAT Phase B Pre-Development Activities”, APR Technologies has delivered an Engineering Model of a monophasic pumped fluid loop for a potential application on a satcom platform under development by TAS and ADS. The thermal regulation system is specified to a qualification operating temperature range between -20 to 70 °C with a thermal conductance between 0 and 3 W/K over a 0.5 m transport length and 1/8” tubing. EHD pumped fluid loop systems have a potential wide range of applications addressing • General heat removal from heat dissipating equipment and payloads. • Closed loop temperature control. For example temperature sensitive sensors. In comparison with heat pipes and thermal conduction, the EHD pumped loop system is particularly suited for thermal switching and temperature control applications. The fluid flow rate is directly controlled by the strength of the electrical field generating the EHD flow and on/off or analogue control schemes can be utilized. Although driven by externally applied electric field, the required energy input is low (0.3W) and much less than typical electrical motors used in mechanically pumped fluid loops. The EHD pump technology developed under this contract is furthermore scalable across a wide range of fluid flow rates, operating temperature ranges and mechanical envelopes. In comparison with heat pipes and Loop Heat Pipes, EHD pumped fluid loops are much less affected by gravitational field thus simplifying ground testing. In comparison with mechanically-pumped fluid loop, EHD pumped fluid loops have advantageously no moving mechanical parts.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.