Optimization Design of Liquid–Gas Jet Pump Based on RSM and CFD: A Comprehensive Analysis of the Optimization Mechanism

The jet pump, a device that entrains and transports fluids using high-speed fluid, is characterized by its simple structure, lack of moving parts, and ease of maintenance. However, its low energy transfer efficiency hinders broader promotion and application. To enhance the entrainment efficiency of the gas–liquid jet pump, this study focuses on optimizing the performance of the liquid–gas jet pump using response surface methodology and numerical simulation. Four key performance parameters—throat length, Nozzle-throat Distance, area ratio, and diffuser angle—are selected for optimization. Computational fluid dynamics (CFD) is utilized for numerical simulation and single-factor optimization analysis is conducted to assess the impact of each parameter on the pump’s performance and to determine each approximate optimal range. Based on these findings, response surface methodology is applied for multi-factor joint optimization. A quadratic polynomial numerical model correlating the factors with the entrainment flow rate is developed through regression analysis, achieving a fitting accuracy of 99.43%. The optimized structural parameters of the gas–liquid jet pump, as predicted by this model, result in a 3.13% increase in peak velocity at the nozzle exit compared to the original design. Additionally, upon ejection, a constant high-speed region of 18 mm is generated at the throat inlet, which constitutes 12.13% of the total throat length. This feature is notably absent in the original design. This leads to a 190.66% increase in the entrainment flow rate, reaching 7.129 m3/h. The significant enhancement in the entrainment performance of the gas–liquid jet pump provides a theoretical foundation for its optimized design.