Solid Diffuser Aerosol Inlet

Short Name or Variable Name:

SDI

HAIS Instrument:

Manufacturer or Builder:

EOL/DFS Shop

TABS

Description

Model:

N/A

Measurements Provided:

Flow rate through the inlet, tube transit pressure

General Description:

The Solid Diffuser Inlet (SDI) is an air sample inlet for aerosol instruments located in the fuselage of the C-130. It is a clone of University of Hawaii SDI that was designed to create iso-kinetic flow conditions at the inlet tip to minimize loss of aerosol particles during passage from the atmosphere into the aircraft cabin for sampling. It is a forward-facing diffuser inlet with a sharp tip. Suction is provided by a blower inside the aircraft. The total volume flow is measured and adjusted with a valve in order to obtain isokinetic flow (velocity at the inlet tip equals flight speed). Three SDI systems are available. They have inlet diameters 4.4 mm,5.9 mm and 5.4 mm (Clarke inlet).
- The photo above shows the SDI inlet mounted on right side of C-130 fuselage, providing air samples to several instruments inside the aircraft. Inlets points into the direction of flight.
- The variation of the SDI shown above has a flow alignment shroud. The Clarke inlet was developed by Tony Clarke (Univ Hawaii) and a copy was made for the C-130. For more information, see documentation link below.
- The hole at the inlet tip is ~5 mm ID and the diffusing cone expands to 38 mm in order to reduce the average velocity by a factor ~60. The cone half-angle is only 4.4 deg, which prevents internal flow separation and re-circulations.
- Edges of the tip are precision machined to have an elliptical cross section shape. This shape reduces the tendency that sharp-edge inlets have for flow separation when the flow is not aligned with the inlet axis.

Measurement Characteristics:

Avoids relative size-sorting of aerosol particles by using isokinetic flow though inlet tip.

Example(s) of Measurement

Monitor inlet flow and pressure against aircraft true airspeed.

Contacts

Lead Contact:

Mike Reeves

Alternate Contact:

Pavel Romashkin

Status/Plans

Current Location:

South Hangar Storage Area

Operational Status:

requestable, ready for deployment

Data

Recent Projects That Used This Instrument:

C-130 chemistry projects

Deployments:

WE-CAN

WINTER

NOMADSS

IDEAS-4_C130

ICE-T

ICE-L

GOTEX

Lifecycle

Date Acquired:

January, 2008

Serial Numbers

Property Tag and/or Serial Number:

Not Available

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