Passive Two-Phase Cooling Circuit With Liquid-Column Pressure Damping
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Passive two-phase cooling systems face significant challenges with irregular pressure fluctuations and pressure surges, which can lead to mechanical stresses and potential system destruction due to condensation-induced pressure peaks, complicating control and stability.
Innovation Solution
Incorporation of a damping tank with adjustable volume and multiple connections to form a liquid column acting as a hydrodynamic vibration damper, decoupling the evaporator and condenser circuits, and creating a stable liquid column to reduce pressure surges and enhance mass flow through the condenser.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a passive two-phase cooling system is used to achieve high heat transport rates with low driving temperature differences, then heat transport efficiency is improved, but pressure fluctuations and pressure surges occur leading to system instability
Solution Approach 1:
A damping tank is introduced as an intermediary component between the evaporator and condenser. This tank receives the two-phase coolant from the evaporator, allows liquid-vapor separation, and supplies stabilized liquid to the condenser. The damping tank acts as a buffer that absorbs pressure fluctuations and prevents direct transmission of pressure surges through the circuit, thereby maintaining system stability while preserving high heat transport rates.
Solution Approach 2:
The cooling circuit is segmented into distinct functional zones: an evaporator section, a damping tank section for phase separation, and a condenser section. By dividing the continuous two-phase flow into separate liquid and vapor handling zones, the system prevents unstable pressure fluctuations from propagating throughout the entire circuit, resolving the contradiction between high productivity and system reliability.
2Reliability
If the damping tank volume is increased to improve pressure stabilization, then system robustness is improved, but device complexity and space requirements increase
Solution Approach 1:
The damping tank is designed to operate passively using natural buoyancy forces for liquid-vapor separation. The geometry of the tank and the density difference between liquid and vapor phases create self-regulating flow patterns without requiring external control mechanisms. This self-service operation simplifies the overall system construction while maintaining effective pressure stabilization, as the tank automatically adjusts to varying flow conditions.
3Ease of operation
If active control means such as electric pumps are used to influence coolant flow, then flow control precision is improved, but system complexity and energy consumption increase
Solution Approach 1:
The patent replaces active mechanical control systems (electric pumps and valves) with passive fluid dynamic control. The damping tank geometry and natural circulation patterns create self-regulating flow control through buoyancy-driven separation and pressure differential management. This substitution eliminates complex active components while maintaining effective flow control, reducing both device complexity and energy consumption.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively reduces or prevents pressure surges, stabilizes flow, increases driving pressure difference, and enhances heat transport performance, resulting in a more robust and efficient cooling system capable of passively dissipating large amounts of heat with low driving temperature differences.
Implementation Method 1
a tubular component is attached to the connection for the condenser return, which enables the formation of a liquid column. This liquid column calms the flow in transient areas by acting as a hydrodynamic vibration damper
Implementation Method 2
the pressure reduction at the outlet of the condenser is achieved by the liquid column, which results in an increase in the driving pressure difference in the condenser and thus an increased mass flow
Implementation Method 3
Two-phase heat transport systems, in which the circulating coolant (also called refrigerant) undergoes a phase transition from liquid to gaseous and back again, enable high heat transport rates
Implementation Method 4
The evaporator 6 is designed as a heat exchanger, which is heated via a thermally coupled heat source 70... The coolant in the evaporator 6 is at least partially evaporated by heat transfer from the heat source 70
Implementation Method 5
The condenser 18 is designed as a heat exchanger which is thermally coupled to a heat sink 72... The coolant vapor is condensed in the condenser 18 by heat transfer to the heat sink 72
Implementation Method 6
liquid coolant and coolant vapor collect in the interior 28 of the damping container 24, with the liquid phase settling down towards the bottom region 38 as a result of the acting gravity and the gaseous/vapor phase collecting above it
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to a passive two-phase cooling circuit (2) with an evaporator (6) and a condenser (18) for a coolant which is conducted in the cooling circuit (2). An evaporator supply line (4) and an evaporator discharge line (10) are connected to the evaporator (6), and a condenser supply line (16) and a condenser discharge line (22) are connected to the condenser (18). Such a cooling circuit is to be developed such that pressure peaks are reduced or even completely prevented during operation while keeping the system design simple and inexpensive. According to the invention, this is achieved in that the evaporator supply line (4), the evaporator discharge line (10), the condenser supply line (16), and the condenser discharge line (22) are connected to a common damping container (24). A liquid column (52) is formed in the condenser discharge line (22) during the operation of the cooling circuit (2), said liquid column assuming the function of a liquid seal (50) and the function of a fluid-dynamic vibration damper.