Study of a Loop Thermosyphon Evaporator for Thermal Control of Aircrafts

2019 ◽  
Vol 141 (9) ◽  
Author(s):  
Gabriela C. Vieira ◽  
Juan Pablo Flórez M ◽  
Marcia B. H. Mantelli
Keyword(s):  
Thermal Management ◽  
External Surface ◽  
Experimental Studies ◽  
Thermal Control ◽  
Heat Sources ◽  
Two Phase ◽  
Aircraft Fuselage ◽  
Start Up ◽  
Thermal Management Of Electronics ◽  
Phase Loop

This work presents experimental studies of a two-phase loop thermosyphon, designed to use the aircraft fuselage low temperatures at high altitude to promote passive thermal management of electronics components in avionics. The main purpose of this work is to develop the evaporator of a loop thermosyphon composed of one evaporator coupled to two condensers presented in the literature. The proposed evaporator comprises ten square stacked copper plates bonded by diffusion. Channels were manufactured in the inner plates so that internal grooves are obtained after the stack is bonded. Studies with concentrated and distributed heat sources over the evaporator external surface are under performance. Parameters such as start-up and operation temperatures will be compared, according to the condition submitted.

Model-Based Dynamic Control of Active Thermal Management System

2017 ◽  
Author(s):  
Nathan Van Velson ◽  
Srujan Rokkam ◽  
Quang Truong ◽  
Bryan Rasmussen
Keyword(s):  
Thermal Management ◽  
Heat Exchangers ◽  
Flow Boiling ◽  
Control Volume ◽  
Dynamic Control ◽  
Two Phase ◽  
Finite Control ◽  
Phase Loop ◽  
Boiling Flow ◽  
And Control

Two-phase cooling technologies, pumped two-phase and vapor compression systems in particular are highly desirable advanced thermal management systems due to the large amounts of heat transfer capabilities available via boiling flow, as well as the inherent isothermality of two-phase processes. However, two-phase heat exchangers face distinctive challenges such as flow boiling instabilities and critical heat flux. In this work, we make developments toward a simulation framework to provide a real-time capability for thermal modeling, simulation and control using embedded software capabilities of Matlab/Simulink. The framework utilizes a highly accurate finite control volume approach to model two-phase heat exchangers, semi-empirical map model for variable speed pump, and one dimensional fluid flow model for pipe. The framework is validated experimentally under transient heat loads against a pumped two-phase loop with two parallel evaporators at Advanced Cooling Technologies, Inc.

Investigation of Carbon Dioxide Explosive Boiling in Single Evaporator of a Two-Phase Mechanically-Pumped Thermal Control Loop

2010 ◽  
Author(s):  
Xi-Hui Sun ◽  
Zhen-Cheng Huang ◽  
Wen-Jia Xiao ◽  
Yue Chen ◽  
Zhen-Hui He ◽  
...  
Keyword(s):  
Reverse Flow ◽  
Thermal Control ◽  
Outer Ring ◽  
Working Fluid ◽  
Two Phase ◽  
Explosive Boiling ◽  
Start Up ◽  
Pressure Spike ◽  
Negative Effect ◽  
Set Up

We investigated experimentally the start-up characteristics of a mechanically pumped two-phase loop (MPTCL), with CO2 as working fluid, and a single evaporator that consists of a bent inner ring and an outer ring constructed by stainless tubes with hydraulic diameter of 2.6 mm and length of 9 m, along which totally 54 pieces of heating element are distributed. Experiments were performed in the following conditions: mass flow rates of 1.1, 2.1, and 3.3g/s; heat loads ranged from 50 to 300W, with the heat-load ratios of the inner ring to the outer ring 2.2:1, 1:1, and 1:2.2 at the operational temperature of −15°C, respectively. During the start-up cases, we detected a reverse flow accompanying with pressure spike, which can be understood as explosive boiling, and a subsequent temporal dry-out phenomenon at the outlet of the evaporator, as a result of explosive boiling. The back flow together with the pressure spike is helpful to set up a two-phase flow all along the evaporator, though it may have negative effect on the loop, especially, when coincident explosive boiling happens. However, such a pressure spike that depends on initial superheating should be controlled to avoid possible harm to the loop.

Ceramic Flat Plate Evaporator for Loop Heat Pipe Cooling of Electronics

2005 ◽  
Author(s):  
Walter Zimbeck ◽  
Jared Chaney ◽  
Patricio Espinoza ◽  
Edward Kroliczek ◽  
David C. Bugby ◽  
...  
Keyword(s):  
Flat Plate ◽  
Heat Pipe ◽  
Temperature Drop ◽  
Working Fluid ◽  
Loop Heat Pipe ◽  
Heat Sources ◽  
Two Phase ◽  
Low Thermal Expansion ◽  
Phase Loop ◽  
Cooling Of Electronics

Two-phase loops are extremely efficient devices for passively transporting heat over long distances with low temperature drop. The heat acquisition component of a two-phase loop, the evaporator, is commonly made from conventional metal materials (aluminum, copper, etc.) and has cylindrical geometry. Neither characteristic is optimally suited for close integration to common electronic or photonic heat sources, which generally have flat interfaces and are constructed from low thermal expansion coefficient (CTE) semiconductor materials. This paper describes the development of a ceramic flat plate evaporator for cooling processor chips in network computers used onboard Navy submarines. The unique requirements of submarines give added motivation for the advantages offered by two-phase loops. The ceramic flat plate evaporator is constructed of low CTE, high thermal conductivity material and thus enables a low thermal resistance interface between the heat source and the working fluid of the loop heat pipe. Alumina and aluminum nitride flat plate evaporators were integrated into a water-based two-phase loop and thermally tested to a heat flux of 30 W/cm2.

Electronics Thermal Management Using Advanced Hybrid Two-Phase Loop Technology

2007 ◽  
Author(s):  
Chanwoo Park ◽  
Aparna Vallury ◽  
Jon Zuo ◽  
Jeffrey Perez ◽  
Paul Rogers
Keyword(s):  
Thermal Management ◽  
High Performance ◽  
Cooling System ◽  
Active Flow Control ◽  
Heat Pipes ◽  
High Heat ◽  
Heat Fluxes ◽  
Significant Advance ◽  
Two Phase ◽  
Phase Loop

The paper discusses an advanced Hybrid Two-Phase Loop (HTPL) technology for electronics thermal management. The HTPL combined active mechanical pumping with passive capillary pumping realizing a reliable yet high performance cooling system. The evaporator developed for the HTPL used 3-dimensional metallic wick structures to enhance boiling heat transfer by passive capillary separation of liquid and vapor phases. Through the testing using various prototype hybrid loops, it was demonstrated that the hybrid loops were capable of removing high heat fluxes from multiple heat sources with large surface areas up to 135cm2 and 10kW heat load. Because of the passive capillary phase separation, the hybrid loop operation didn’t require any active flow control of the liquid in the evaporator, even at highly transient and asymmetrical heat inputs between the evaporators. These results represent the significant advance over state-of-the-art heat pipes, loop heat pipes and evaporative spray cooling devices in terms of performance, robustness and simplicity.

Experimental study on the transient behaviors of mechanically pumped two-phase loop with a novel accumulator for thermal control of space camera payload

2020 ◽  
Vol 179 ◽  
pp. 115714
Author(s):  
Qingliang Meng ◽  
Zhenming Zhao ◽  
Tao Zhang ◽  
Johannes van Es ◽  
Aswin Pauw ◽  
...  
Keyword(s):  
Experimental Study ◽  
Thermal Control ◽  
Two Phase ◽  
Phase Loop

Vibration/Shock-Tolerant Capillary Two-Phase Loop Technology for Vehicle Thermal Control

2008 ◽  
Author(s):  
Xudong Tang ◽  
Chanwoo Park
Keyword(s):  
High Performance ◽  
Low Cost ◽  
Thermal Control ◽  
Small Scale ◽  
Manufacturing Cost ◽  
Two Phase ◽  
Loop Heat Pipes ◽  
Military Vehicles ◽  
Phase Loop

Two-phase thermal management technologies are promising cooling solutions for the high performance electronics in the next generation military and commercial vehicles. However, vibrations (∼ 10Grms in commercial automobile engines and transmissions) and shocks (30G to 1,200G in military combat vehicles, caused by gun firing, ballistic launch and abrupt maneuvering) present a severe challenge to any capillary-driven (i.e., passive) two-phase devices. A low-cost, vibration/shock-tolerant Capillary Two-Phase Loop (CTPL) technology was developed as a cooling alternative for the future military vehicles. Unlike the traditional two-phase cooling loops such as Loop Heat Pipes (LHP) and Capillary Pumped Loops (CPL), the CTPL offers the following advantages: (1) lower manufacturing cost by sintering the evaporator wick in-situ; (2) improved tolerance to vibrations and shocks due to the improved mechanical strengths of the in-situ sintered wick; (3) improved heat flux performance because of the non-inverted meniscus wick. Small-scale proof-to-concept CTPL prototypes were successfully tested up to 120W of heat input and under multiple, consecutive shocks of up to 6.6G.

Spacecraft Thermal Management Using Advanced Hybrid Two-Phase Loop Technology

2007 ◽  
Author(s):  
Chanwoo Park ◽  
Aparna Vallury ◽  
Jon Zuo ◽  
Jeffrey Perez ◽  
Paul Rogers
Keyword(s):  
Thermal Management ◽  
Two Phase ◽  
Phase Loop
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