Two-phase refrigerant pump bladder control system
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Solution Overview
Problem
Conventional two-phase pump loop (TPPL) systems face challenges with flow instability and temperature oscillations during transient operations, affecting stability and temperature control in heat-generating devices like high-energy lasers.
Innovation Solution
A bladder control system using an expandable bladder and air compressor to regulate refrigerant flow by expanding or contracting the bladder to maintain precise saturation pressure, thereby controlling temperature fluctuations and stabilizing the system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional TPPL systems operate during transient conditions, then the system can transition between idle and fire operations, but flow instability and temperature oscillations occur
Solution Approach 1:
The patent implements a feedback control system using a pressure sensor to monitor refrigerant pressure and a controller to regulate the bladder's volume accordingly. The controller adjusts the bladder volume based on feedback from the pressure sensor to maintain saturation pressure within a desired range, eliminating flow instability and temperature oscillations during transient operations between idle and fire conditions.
Solution Approach 2:
The patent introduces a dynamic bladder volume control mechanism that actively adjusts the refrigerant storage capacity during transient operations. The bladder's variable volume allows the system to adapt to changing thermal loads and operational conditions, maintaining stability during transitions between idle and fire operations by dynamically balancing refrigerant supply.
2Speed
If the TPPL system maintains saturated liquid conditions during idle operations, then the system is ready for rapid response, but pressure control becomes challenging during transient operations
Solution Approach 1:
The feedback control system continuously monitors saturation pressure and adjusts the bladder volume to maintain pressure within the desired range. The controller receives pressure feedback from the sensor and modulates the bladder actuator accordingly, enabling precise pressure control during transient operations while maintaining the ability for rapid system response.
Solution Approach 2:
The bladder is pre-charged with refrigerant during idle operations to maintain saturated liquid conditions and readiness for rapid response. This preliminary preparation allows the system to quickly transition to fire operations while the feedback control system subsequently adjusts the bladder volume to maintain precise pressure control during the transient transition.
3Power
If the condenser removes excess heat during fire operations, then the system handles high thermal loads, but temperature control at the heat load becomes less stable
Solution Approach 1:
The feedback control system monitors saturation pressure, which directly correlates with temperature in a two-phase system. By maintaining saturation pressure within a narrow range through bladder volume adjustment, the system ensures temperature stability at the heat load even during high-power fire operations where the condenser is removing excess heat.
Solution Approach 2:
The patent controls the saturation pressure parameter through bladder volume adjustment, which in turn controls the saturation temperature. By maintaining pressure within a desired range during fire operations, the system ensures that the evaporator temperature remains stable despite varying heat removal rates in the condenser, providing consistent temperature control at the heat load.
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 system effectively maintains tight temperature control and reduces flow instabilities during transient operations, ensuring stable operation of heat-generating devices by managing refrigerant pressure within specified limits.
Implementation Method 1
an expandable bladder located within the refrigerant tank and having a port selectively connected to the outlet of the air compressor... Expansion of the expandable bladder discharges refrigerant from the bladder tank though the port of the bladder tank and contraction of the expandable bladder intakes refrigerant into the bladder tank
Data Source
AI summary
A bladder control system for a two-phase pump loop (TPPL) includes an air compressor, an air line connected to the air compressor, first and second solenoid valves located along the air line, a refrigerant tank having a port operatively connected to the TPPL for selective flow of refrigerant between the refrigerant tank and the TPPL, an expandable bladder located within the refrigerant tank and having a port connected to the air line between the first and second solenoid valves for selective flow of air between the expandable bladder and the air line, and a controller. The controller selectively expands and contracts the expandable bladder to control flow of refrigerant out of the refrigerant tank to the TPPL and into the refrigerant tank from the TPPL for maintaining the system refrigerant pressure within a desired tight range. This is particularly useful for obtaining tight temperature control at the thermal load.