Preliminary Design and System Considerations for an Active Hybrid Laminar Flow Control System

Abstract

Hybrid laminar flow control or HLFC design is a complex and multi-disciplinary process, which demands a thorough understanding of all aspects from a global systems viewpoint. The objective of the paper is to present a preliminary design of important components of an HLFC system that helps in quick assessment of conceptual system architectures. This is important to evaluate feasibility, system performance, and overall aircraft benefits at early stages of system development. This paper also discusses the various important system requirements and issues concerning the design of active HLFC systems, and the interfaces between various disciplines are presented. It can be emphasized from the study that the future compressor design for the HLFC system should consider the thermal management aspects and additional mass flow requirements from the aerodynamics-structure design optimization and also from water drain system solutions. A method to calculate the accumulated water content inside the plenum chambers is presented, and the effect of a drain hole on the power consumption is studied. A low order thermal management study of the HLFC compressor motor shows a high temperature rise in the windings for very high speed motors for long duration operation and calls for effective cooling solutions.

Assessment of Future Airframe and Propulsion Technologies on Sustainability of Next-Generation Mid-Range Aircraft

“…An additional consideration was taken to estimate the effect of the suction system mass on laminar flow. Kalarikovilagam [60] and Iyer [61] performed preliminary sizing of vertical and horizontal stabilizers of mid-range and long-range commercial jets using the physics-based approach and also performed design trade studies with respect to the number of compressors required for the suction system. Studies showed that horizontal and vertical stabilizers correspond to 0.11% and 0.16% of the empty mass, respectively, for two airplanes of different classes.…”

The Suction Panel - xHLFC and Structural Solution for Energy Efficient Aviation

“…Similarly, the mass of the casing of the compressor was calculated to 2.43 . Finally, the approximate mass of motor needed for the compressor can be estimated according [10] as 4.9 . The total mass of the compressors assuming three compressors per wing is the summation of this masses.…”

“…(2) To calculate the compressor mass, an approximation based on the work conducted by Srinivasan et al [10] is adopted. The design parameters important from the aerodynamic system are the plenum pressure and the pressure ratio of the compressor.…”

“…At the flight altitude the compressor should increase the pressure from 31806 Pa to atmospheric pressure of 35650 Pa which means a pressure ratio of approximately 1.12. Based on the study findings considering various layouts for the HLFC compressor, a system architecture where the compressor is kept close to the suction region is the best suited owing to the least ducting mass requirement [10]. Table 1 shows the mass flow requirement of suction chambers, ref.…”

Review of Adaptive Shock Control Systems

“…Moreover, any porous surface concept in aeronautical applications (e.g., hybrid laminar flow, suction, blowing etc. [31,[99][100][101]) is susceptible to blockages from daily operations, and in this case may inhibit the re-circulation of the airflow. Consequently, an adequate solution needs to be found to purify the porosity from particles or prevent the contamination at all.…”