Cryogenic Nozzle Flow Control via Throttling Gas Mixing
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Solution Overview
Problem
Conventional methods for controlling the flow rate of cryogenic liquids through nozzles face issues such as pressure drop, boil-off, nozzle plugging, and the need for oversized nozzles, which lead to reduced spray velocity and complex system designs, and are costly due to the use of valves that break down easily.
Innovation Solution
A method and apparatus that utilize a throttling gas with a pressure greater than or equal to the cryogenic liquid, and a temperature greater than the cryogenic liquid, to control the flow rate by introducing the gases into a contact zone where they form a resulting fluid, which is then discharged through a nozzle, allowing for adjustment of mass flow rate and liquid-to-gaseous ratio without a conventional flow-restricting valve.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a valve is installed upstream of the nozzle to control flow rate, then the flow rate can be reduced, but the spray velocity is reduced and boil-off occurs causing nozzle plugging
Solution Approach 1:
The invention extracts the flow control function from the traditional valve upstream of the nozzle and relocates it to a flow control member integrated at the nozzle. This eliminates the pressure drop caused by separate valves while maintaining flow rate control capability, thereby preserving spray velocity and preventing boil-off plugging.
Solution Approach 2:
The invention introduces a throttling gas as an intermediary substance that mixes with the cryogenic liquid in a mixing chamber. This gas acts as a mediator to control the effective flow rate through the nozzle without creating the harmful pressure drop that would reduce spray velocity or cause boil-off.
2Reliability
If the nozzle orifice is increased in size to vent boil-off quickly, then flow rate pulsations are eliminated, but the nozzle becomes too large and requires higher valve restriction
Solution Approach 1:
The invention replaces the mechanical approach of using a large nozzle orifice with a gas-based flow control mechanism. The throttling gas mixed with the cryogenic liquid in the mixing chamber provides smooth flow rate control without requiring a large nozzle opening, thus eliminating flow rate pulsations while maintaining a compact nozzle size.
3Productivity
If a larger nozzle is used to vent vapor during cool-down, then vapor venting is improved, but the nozzle must be changed or the system becomes complex
Solution Approach 1:
The invention makes the effective nozzle opening dynamic through the flow control member that adjusts the mixture of cryogenic liquid and throttling gas. During cool-down, the system can quickly vent vapor by adjusting the gas-to-liquid ratio without physically changing the nozzle, providing rapid response while maintaining simple system architecture.
4Quantity of substance
If conventional valves are used to handle cryogenic liquids, then flow control is achieved, but the valves are costly and break down frequently
Solution Approach 1:
The invention extracts the flow control function from the unreliable conventional valve and implements it through a flow control member designed specifically for cryogenic applications. This member uses the throttling gas mechanism to control flow without the mechanical complexity and reliability issues of traditional valves, thereby improving system reliability while maintaining flow control capability.
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
This approach allows for controlled flow rates without reducing spray velocity, enables larger nozzle sizes for rapid response and start-up, and eliminates the need for costly valves, providing a versatile solution for various industrial applications.
Implementation Method 1
A method and apparatus for controlling the flow rate of a cryogenic liquid through a nozzle. The flow rate is controlled with a 'throttling' gas having a pressure greater than or equal to the pressure of the cryogenic liquid, a temperature greater than the temperature of the cryogenic liquid; and a boiling point less than or equal to the temperature of the cryogenic liquid
Implementation Method 2
introducing the cryogenic liquid and the throttling gas into a contact zone and contacting the liquid and the throttling gas to form a resulting fluid
Data Source
AI summary
A nozzle and process are set forth for contacting a cryogenic liquid and a gas, and discharging the resulting fluid through the nozzle. In one embodiment, the ratio of the discharged fluid's liquid component to its gaseous component is controlled as a function of the gas pressure.