Intake Design Effects on Inertial Particle Separator Performance
Creators: name:  A.B. DALDAL 
name:   S. EYI 
Publisher: name: Proceedings of  the 9th European Conference for Aerospace Sciences. Lille, France, 27 June - 1 July, 2022
Year: 2022
Subjects: PROPULSION PHYSICS
AIR BREATHING
RAMJET
SCRAMJET

description: In many engineering applications, there are numerous undesirable objects which are generally known as Foreign Object because of their dangerous effects. Dust, sand, stones, salt spray, birds, ice, snow and metal parts are very usual examples of foreign object for helicopters [1]. Especially sand and dust are the most common foreign object sources which are responsible from the compressor erosion due to large number of dangerous operation areas. Inertial particle separator (IPS) is a device located at the frontmost of an engine which is designed to protect it from these foreign objects. It provides protection by deflecting both air and particle flows outward direction, where dust/sand particles, which has higher inertia, move into the scavenge part and air, which has lower inertia, turn back to the core of the engine. When an engine with an integrated IPS is installed on a helicopter, a suitable intake design is needed to satisfy the required airflow. There are several parameters that affects characteristics of the IPS flow due to intake designs such as distortion and swirl. Moreover, compressor rotation, helicopter attitudes (sideslip and pitch angle), rotor interactions and gust affect the swirl type (bulk, twin and offset swirl), angle, and direction in conjunction with the intake design. In the literature, all studies assume that the incoming flow to the IPS is uniform and straight, however this is not true for installed engines. In this study, only bulk swirl effects on the IPS performance is investigated in terms of efficiency by using computational fluid dynamics (CFD). Computational method is validated with an experimental data [2], which has 2% uncertainty, with an error less than 3% at low ? (scavenge to core air mass flows ratio). CFD analyses are performed with Star-CCM+ software at Linux based high performance computing (HPC) cluster by using unsteady approach and turbulence is modeled with Improved Delayed Detached Eddy Simulation (IDDES) model. Lagrangian approach is used to simulate particle motion with one-way coupling option. Changes in flow properties due to particle motion is so small hence, it is neglected. Particles are modelled as spherical and Schiller-Naumann correlation is used for drag force estimation. After the validation, a 3-D annular IPS geometry is created by using Siemens NX; however, only the 24 slice of this geometry is analyzed to reduce computational power. Flow domain is discretized with 8 million hexahedron volume elements. It is important to note that this is the first multi-phase unsteady analysis of a 3-D annular IPS geometry with the most accurate simulation approach [3]. 15 bulk swirl is given as an input from the intake boundary in addition to the incoming flow. Pressure outlet boundary with target mass flow rate option is used at the end of scavenge and core parts. Results show that, 1% increase in efficiency is obtained with 15 swirling flow for ? = 0.16 by using ISO-12103 A4 course sand distribution. Similar studies are going to be performed for ? = 0.10 and ? = 0.20 and their results are going to be shared later.