Analysis of bearing lubrication technology for gas turbine machinery: Application of grease lubrication, oil-gas lubrication and jet lubrication

In the field of gas turbine machinery, gas turbomachinery bearings are key components that support rotating parts and ensure stable operation of machinery. The selection and design of their lubrication methods are directly related to the performance, life and operating efficiency of the equipment. There are various lubrication methods for gas turbine machinery bearings, among which the most common ones include grease lubrication, oil-gas lubrication and jet lubrication.

1. Overview of lubrication methods for gas turbine machinery bearings
The working environment of gas turbine machinery is harsh, and high temperature, high pressure and high speed are its typical characteristics, which puts extremely high demands on the lubrication of bearings. Grease lubrication, oil-gas lubrication and jet lubrication have their own characteristics and are suitable for different operating conditions and requirements.

Grease lubrication is known for its simple structure and easy maintenance. It is suitable for a wide range of speeds, especially in the low to medium speed range. It provides continuous lubrication through grease encapsulated in the bearing cavity, reducing the risk of external contamination.
Oil-gas lubrication effectively reduces friction and wear by continuously supplying a trace amount of oil mist to the bearing contact surface. It is particularly suitable for high-speed and heavy-load conditions, and can significantly reduce energy consumption and temperature rise.
Jet lubrication directly impacts the rolling elements and raceways of the bearings by spraying lubricating oil at high pressure. It is suitable for occasions with extremely high temperatures, heavy loads or rapid heat dissipation. Although the system is complex, the lubrication effect is significant.
2. In-depth analysis of grease lubrication
Grease lubrication is one of the most traditional lubrication methods in gas turbine machinery. Its main shaft structure design is relatively simple and cost-effective, so it is widely used in many fields. The selection and amount of grease used are the key factors that determine the effect of grease lubrication.

Selection of grease: High-quality grease should have good extreme pressure anti-wear, oxidation resistance, rust resistance and low-temperature fluidity. For gas turbine machinery, grease with synthetic oil (such as diester, diester + mineral oil, etc.) as the base oil is the first choice due to its excellent thermal stability and lubrication performance. Grease with NLGI (National Lubricating Grease Institute) grade 1 or 2 not only ensures good filling and pumping properties, but also effectively reduces the heating problem caused by stirring.
Control of the amount of grease used: When running at high speed, excessive grease will increase the stirring resistance inside the bearing, resulting in a sharp increase in heat generation and affecting the bearing life. Therefore, it is crucial to accurately control the amount of grease filled. Generally, the amount of grease filled in the bearing cavity should be controlled between 1/3 and 1/2 of the internal space of the bearing, and the specific value needs to be determined comprehensively according to the bearing type, speed and working environment.
Grease replacement and maintenance: Regular inspection and replacement of grease is the key to maintaining good lubrication of the bearing. A reasonable grease replacement plan should be formulated based on the recommended cycle of the equipment manufacturer and the actual operating conditions. At the same time, pay attention to the cleanliness of the bearing cavity to avoid impurities from mixing in and affecting the lubrication effect.
3. Optimization strategy of grease lubrication
With the development of material science and lubrication technology, grease lubrication is also constantly innovating. For example, nano-additives are used to improve the extreme pressure and anti-wear properties of grease; adaptive temperature control lubrication systems are developed to automatically adjust the supply and type of grease according to the bearing temperature to achieve more accurate and efficient lubrication management.

The lubrication of gas turbine machinery bearings is a systematic project. It is necessary to select the appropriate lubrication method according to the specific working conditions, and combine lubrication materials, lubrication system design and maintenance strategies to comprehensively improve the reliability and operation efficiency of the equipment. Grease lubrication still occupies an important position in the field of gas turbine machinery due to its unique advantages, and continuous exploration and optimization of grease lubrication technology will be the key to further improving the performance of gas turbine machinery.