Liquid Hydrogen Pump With Dual Thrust Balance Mechanisms
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Solution Overview
Problem
Existing pump apparatuses for liquid hydrogen face challenges in canceling axial thrust and preventing gasification, leading to bearing wear and vibration due to the low viscosity and easy gasification of hydrogen, which are not adequately addressed by traditional thrust balance mechanisms.
Innovation Solution
A pump apparatus with a combination of first and second thrust balance mechanisms, including variable and fixed-gap types, that generate sufficient upward forces to cancel the weight and axial thrust of the rotational structure, and prevent gasification by controlling fluid communication and pressure differentials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a traditional thrust balance mechanism is used, then axial thrust is partially canceled, but the upward force is insufficient due to liquid hydrogen's low density, resulting in continued bearing load
Solution Approach 1:
The thrust balance mechanism is divided into multiple independent chambers (first high-pressure chamber, first low-pressure chamber, second high-pressure chamber, second low-pressure chamber) separated by partitions. This segmentation allows independent pressure control in each chamber, enabling the generation of sufficient upward force to compensate for the low density of liquid hydrogen while maintaining system stability.
2Stress or pressure
If liquid hydrogen moves from high-pressure chamber to low-pressure chamber, then pressure equalization occurs, but gasification happens due to pressure drop, forming bubbles that cause vibration and performance loss
Solution Approach 1:
An intermediary communication line is introduced to connect the high-pressure chamber and low-pressure chamber through a controlled pathway. This intermediary structure allows pressure equalization to occur gradually and controllably, preventing sudden pressure drops that would cause gasification. The intermediary line acts as a buffer, maintaining liquid hydrogen in a stable state while still achieving pressure balance.
3Strength
If the bearing is immersed in liquid hydrogen for lubrication, then friction is reduced, but wear increases due to liquid hydrogen's very low viscosity
Solution Approach 1:
The thrust balance mechanism generates an upward force that counteracts the weight of the rotational structure (impeller, shaft, and associated components). By balancing the axial thrust and weight, the bearing operates with minimal radial and axial loads, significantly reducing wear despite the low viscosity of liquid hydrogen. The counterbalancing force compensates for the insufficient lubrication effect, extending bearing life.
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 combined thrust balance mechanisms effectively reduce bearing load to zero, prevent hydrogen gasification, and maintain stable operation by ensuring bubble-free fluid flow, thereby extending bearing life and ensuring consistent pumping performance.
Implementation Method 1
The thrust balance mechanism is configured to generate an upward force by a pressure difference between the high-pressure fluid and the low-pressure fluid, and to cancel the axial thrust and the weight of the rotor with this upward force.
Implementation Method 2
a pump apparatus for pressurizing liquid hydrogen, comprising: a rotation shaft; a plurality of impellers fixed to the rotation shaft
Implementation Method 3
The bearing is immersed in liquid hydrogen and is lubricated by the liquid hydrogen.
Implementation Method 4
the pump apparatus further comprises a check valve attached to the return line to allow the liquid hydrogen to flow only from the low-pressure chamber to the suction-side impeller
Data Source
AI summary
The present invention relates to a pump apparatus for pressurizing liquid hydrogen, and more particularly to a pump apparatus equipped with a thrust balance mechanism for canceling axial thrust acting on an impeller. The pump apparatus includes a rotation shaft (1), a plurality of impellers (2a to 2h) fixed to the rotation shaft (1), bearings (5, 6) for rotatably supporting the rotation shaft (1), a pump casing (7) for housing the plurality of impellers (2a to 2h), and a first thrust balance mechanism (20) and a second thrust balance mechanism (40) for canceling the weight of a rotor including the rotation shaft (1) and the plurality of impellers (2a to 2h) and the axial thrust acting on the plurality of impellers (2a to 2h).