Investigation of cryogenic seal durability for LNG piston pumps

韦斯特波特电力公司，BC总部位于温哥华，是一家提供基本技术和专有解决方案的全球供应商，这些技术和解决方案使发动机能够使用经济和环境可持续的燃料，如天然气、丙烷和氢气。天然气发动机提供了比汽油或柴油基发动机更低的温室气体、氮氧化物和颗粒物排放的优点，因此可以在向低碳运输系统的转变中发挥重要作用。发动机和LNG储罐系统的开发和优化是促进天然气发动机更广泛应用的重要组成部分。这种系统的一个重要组成部分是用于从LNG储罐输送液态天然气的往复式LNG泵。往复式活塞泵在活塞的进气冲程期间通过止回阀将液态天然气从罐吸入气缸中。然后将其压缩并加压，从20至230 psi（通常为储罐压力）加压至4500 psi，然后通过 在活塞的压缩冲程期间，第二止回阀。往复泵中的活塞包括围绕活塞的一组环形密封件，以阻止活塞和气缸之间的流动。这些密封圈在决定泵的效率和耐用性方面起着关键作用。在高压返回冲程过程中，存在通过环形密封件的泄漏流，并且密封件和气缸之间的摩擦取决于每个密封件的接触压力和活塞速度。密封件的性能因磨损而降低，磨损取决于密封环和气缸之间的接触压力、摩擦力和滑动速度。因此，重要的是要了解通过密封件的流量，以优化密封件的性能和耐用性，进而优化往复活塞泵的性能和耐用性。本项目的总体目标是对通过密封件的流量进行建模和计算，以评估接触压力和摩擦，并确定不同操作条件和密封装置设计下通过密封装置的泄漏流量。结果将用于确定对密封性能影响最大的因素，并优化密封设计。

Westport Power Inc., headquartered in Vancouver, BC is a global provider of essential technologies and proprietary solutions that allow engines to operate on economically and environmentally sustainable fuels such as natural gas, propane and hydrogen. Natural gas engines offer advantages of lower emissions of greenhouse gases, nitric oxides, and particulate matter than gasoline or diesel based engines and thus, can play an important role in the shift toward a lower carbon transportation system. Development and optimization of the engines and LNG tank systems are an important part of facilitating the broader implementation of natural gas engines. An important component of such systems is the reciprocating LNG pumps used to transfer the liquid natural gas from the LNG storage tanks. The reciprocating piston pumps draw liquid natural gas from the tank into the cylinder through a check valve during the intake stroke of the piston. It is then compressed and pressurized from the 20 to 230 psi typical of the storage tank pressure up to 4500 psi, before being exhausted through a second check valve during the compression stroke of the piston. The piston in the reciprocating pumps includes a set of ring seals around the piston to impede flow between the piston and cylinder. These ring seals play a key role in determining the efficiency and durability of the pumps. There is leakage flow through the ring seals during the high pressure return stroke process, and also friction between the seals and cylinder that depends on the contact pressure of each seal and the piston speed. The performance of the seals is degraded by wear that depends on the contact pressure, friction and sliding velocity between the ring seal and cylinder. Thus, it is important to understand the flow through the seals in order to optimize the performance and durability of the seals and in turn the reciprocating piston pump. The overall objective of this project is to model and compute the flow through the seals in order to assess the contact pressure and friction, and determine the leakage flow through the seal sets for different operating conditions and seal set designs. The results will be used to identify factors that have the largest influence on seal performance and optimize the seal design.