Inverse design tool for rotary positive displacement machines with liquid injection

该项目的目标是开发一种工具，用于在腔室模型模拟的基础上进行液体喷射的旋转容积式机器（RPDM）（例如双螺杆机器，旋转叶片机器）的逆向设计，该工具提供给优先方案的参与者，用于模拟热力循环（压缩机或膨胀机）中的流体能量机器。逆向设计工具的输入参数是来自所选过程的要求，即除了流体类型和质量流率之外，RPDM的入口端口、注射喷嘴和出口端口处的流体条件（例如压力、温度、蒸汽质量）。要反向确定的设计参数是机器几何形状和速度。在该工具内，设计参数在能量效率方面被优化。机器几何形状的优化不仅限于机器尺寸，还包括RPDM的特定无量纲几何参数（例如内置体积比、包角、直径与长度比），特别关注流体依赖性。已知RPDM设计中的关键因素是正确确定流体相关效应，例如两相间隙质量流率、蒸发或冷凝引起的热传递以及机器入口和出口端口中的节流效应。概述的目标与各种科学挑战有关。一方面，它需要为RPDM自动生成腔室模型。需要将几何抽象为容量（例如体积、机器部件）及其连接，以进行质量和/或能量交换。此外，还需要有效的容量之间质量和能量交换模型（例如，通过间隙或阀门/开口的多相流，相变和传热模型）。在这方面，该项目的一个重点将是开发有效的模型，用于注入RPDM工作室的液体（工作流体或辅助流体，例如油的质量流率）的影响。关于液体射流的时间发展，液体在旋转工作室中的时间依赖性分布以及气相和液相之间的质量和热传递的问题被采用，并使用通用试验台和伴随的数值实验研究。关于卡诺电池，通过注入液相将RPDM的出口温度调节到工艺的温度要求的可能性-同时保持机器的最佳压力比-似乎是有利的。

The objective of the project is to develop a tool for the inverse design of rotary positive displacement machines (RPDM) (e.g. twin-screw machines, rotary vane machines) with liquid injection on the basis of a chamber model simulation, which is provided to the participants of the Priority Programme for modelling the fluid energy machine within thermodynamic cycles (compressor or expander). Input parameters for the inverse design tool are the requirements from the selected process, i.e. in addition to the type of fluid and the mass flow rates, the fluid conditions at the inlet port, injection nozzle and outlet port of the RPDM (e.g. pressure, temperature, vapour quality). The design parameters to be inversely determined are the machine geometry and the speed. Within the tool the design parameters are optimized with regard to energetic efficiency. The optimization of machine geometry is not only limited to machine size, but also includes specific dimensionless geometric parameters of RPDM (e.g. build-in volume ratio, wrap angle, diameter to length ratio) with particular focus on the fluid-dependency. Crucial factors in the design of the RPDM are known to be the correct determination of the fluid-dependent effects, such as the two-phase gap mass flow rates, the heat transfers due to evaporation or condensation, and the throttling effects in the inlet and outlet ports of the machine. The outlined objective is associated with various scientific challenges. On the one hand, it requires an automated chamber model generation for the RPDM. Abstraction of the geometry into capacities (e.g. volumes, machine parts) and their connections for exchange of mass and/or energy is needed. Furthermore, valid models for the exchange of mass and energy between the capacities are required (e.g. multiphase flows through gaps or valves/openings, phase change and heat transfer models). In this respect, one focus of the project will be the development of valid models for the effects of an injected liquid (mass flow rate of the working fluid or an auxiliary fluid, e.g. oil) into the working chambers of the RPDM. Questions about the temporal development of the liquid jet, the time-dependent distribution of the liquid in the rotating working chambers and the mass and heat transfer between gas and liquid phases are taken up and investigated experimentally using a generic test rig and accompanying numerically. With respect to the Carnot battery, the possibility to adjust the outlet temperature of the RPDM to a temperature requirement for the process by injecting a liquid phase - while maintaining an optimal pressure ratio for the machine - appears to be advantageous.