Browsing by Author "Kulakov, Andrei"
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Item Integrated Thermal Architecture based on Advanced Control Loop (ACL) with multiple evaporators and condensers(50th International Conference on Environmental Systems, 7/12/2021) Campo, Sa�l; Romera, Francisco; Kulakov, Andrei; Torres, AlejandroA highly-integrated thermal architecture based on Advanced Control Loops (ACLs) has been developed and tested. This architecture consists of a Constant Conductance Heat Pipe (CCHP) network thermally connected to two ACLs. Heat-dissipating units are mounted on the CCHP network. Each ACL has 4 independent evaporators and 4 independent condensers, in the sense that they can be coupled to independent power dissipation sources or sink conditions respectively. The CCHP network has 4 primary CCHPs and 4 spreader CCHPs which serve to equalize the heat load between the primary CCHPs. The CCHP network can be embedded in a honeycomb panel to act as an equipment panel or deck. The ACL cylindrical evaporators, without the thermal interface flanges (saddles), are embedded in dedicated bores as part of the primary CCHP extruded profiles. In this way, the overall thermal gradient between the dissipating units and the condensers is minimized by eliminating the standard bolted interface between evaporator and CCHP flanges. An extensive thermal test campaign was performed on the ACL to validate the novel thermal architecture concept, to characterize the system performance under worst-case operational conditions, and to determine the system performance envelope. The campaign included a number of tests: thermal performance (conductance and heat transfer capability) under various power conditions and with a �split� (ACLs share the thermal sink) and �nonsplit� (each ACL has a dedicated thermal sink) condenser design, minimum and maximum power, start-up, transient input power and heat sink temperature variations, and NCG influence. To cope with transients in the power and thermal boundary conditions, an innovative method of control is also presented. Ammonia is selected as the working fluid for both CCHPs and ACLs taking into account the standard operating and non-operating temperature ranges of most heat-dissipating electronics.Item Mechanically Pumped Advanced Control Loop: a Solution for High Power Platforms(50th International Conference on Environmental Systems, 7/12/2021) Campo, Sa�l; �lvarez, Jes�s; Kulakov, Andrei; Romera, Francisco; Lara, �scar; Torres, AlejandroTwo-phase mechanically pumped loops have been identified as the potential solution for the heat management of high-powered platforms, such as next generation telecommunications satellites. The proposed concept Mechanically Pumped Advanced Control Loop (M-ACL) combines the advantages of a two-phase modular thermal control system and a mechanically pumped loop. In single-phase fluid loops temperature rise in the fluid and flow rate are directly proportional to the required heat transfer rate. High cooling loads lead to a large temperature rise and high pump power. For more effective thermal transport, the single-phase loop can be replaced by a two-phase one. This allows employing the latent heat of vaporization to significantly reduce flow rates, decrease temperature gradients, and increase heat transfer coefficients. M-ACL concept has been defined after an extensive literature and patents review. It is based on the multi-evaporator, multi-condenser Advanced Control Loop (ACL) concept, which means an integrate solution for the complete thermal control of the platform. The implementation of a mechanical pump in the system means an important increase of the heat transport capability that depends on the pump pressure rise characteristic. A trade-off has been performed to define main mechanical pump and M-ACL features. Additionally, a M-ACL engineering model has been designed based on a NACPA pump from RealTechnologie AG. In this study, the detailed design is presented as well as simulation results using a thermo-hydraulic model developed in EcosimPro simulation tool.