NCAR HIAPER Modular Inlet

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NCAR HIAPER Modular Inlet - HIMIL

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NCAR Earth Observing Laboratory (EOL) is developing a general purpose air sample inlet for use on the new HIAPER Gulfstream-V aircraft. The design concept is modular, so that its components can be changed or custom-built to meet the particular needs of the measurement and instrument it serves.

Design goals

Two kinds of inlets will be designed, built, installed, and tested: (1) a trace gas inlet for ozone and carbon monoxide; (2) two versions of a small aerosol inlet -- one forward-facing and one aft-facing (target particles 5 nm to 2 痠 diameter). Features that are common to both the trace gas and aerosol inlets include:

heating to reduce risk of rime ice blocking the inlet in supercooled water clouds
shortest distance from inlet tip to instrument
chemically inert interior
sample from free stream, outside the aircraft flow boundary layer (scales to ~1% of distance from nose)
minimize obstruction or interference with other sensors
minimize obstruction and hazard to crew working near inlets & piping
avoid compression heating of sample
minimize aerodynamic drag

More information is available in the Development Plan.

Basic Features

The proposed HIAPER Modular Inlet design has the following features.

modular: hollow strut supports independent forward, mid-body, and aft sections
optional shroud for flow-alignment or deceleration
inlet configurable as forward or aft-facing or flow-through or multiple feeds
inlet tip can be sharp-edged, rounded ellipse cross section, blunt, diffuser
inlet tip can be made from a variety of materials
specialty tubing can feed through interior (teflon, stainless steel, etc.)
heating of forward-facing edges, with temperature control of heated sections
mounts on fuselage aperture pad (6 locations on top; 2 on belly)

section view
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Dimensions

inlet axis 19 cm from skin of aircraft
strut interior has open area, elliptical shape ~3 cm x 10 cm with structure to secure interior components

(click for larger)

Development Activities

Current work on this new design includes soliciting comments from the scientific community, analyzing aerodynamic loads, and airflow modeling. Basic versions of the inlet will be built to support the Progressive Science flights in the fall 2005. More information about this inlet will be posted to this website or can be obtained from EOL staff (Fox, Rogers, Lord).

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