The wireless intelligent water distributor is an emerging technology increasingly applied in oilfields to enhance oil recovery. Although the system has many advantages, the high energy consumption of its integrated control valve hinders its adoption in long-term applications. However, existing studies have not sufficiently captured the mechanical characteristics of forces acting on the spool, particularly under the influence of multiple coupled factors, such as fit clearance, deflection, and fluid-structure interaction, which limit the ability to accurately assess energy consumption. To address this gap, this study develops a comprehensive energy consumption model of the control valve, specifically addressing the design of fit clearance, a critical factor influencing energy efficiency. Utilizing a loosely coupled fluid–structure interaction algorithm, we established a mechanical model of the spool to investigate the fluid-solid interaction mechanisms within the fit clearance. For the first time, the effects of contact friction on energy consumption are incorporated. An optimization algorithm was then applied to determine the optimal fit clearance by balancing low friction and minimal leakage. The validity of our numerical model was confirmed through comparison with both theoretical and experimental results. Our results demonstrate that the fit clearance has a pronounced impact on the valve's energy usage: the total maximum energy consumption for one full stroke with a 0.05 mm clearance is 3.33% higher than with a 0.25 mm clearance. When the spool is independently driven, this value is 7.21%. The optimal fit clearance is determined to be 0.127 mm. These results can improve the overall performance and extend the service life of intelligent water distributors. The findings and models developed in this study provide essential theoretical support and practical strategies for optimizing control valve energy consumption.