Microstructural and loading characteristics of diesel aggregate cakes

Jingxian Liu, Jacob J. Swanson, David B. Kittelson, David Y.H. Pui, Jing Wang

Research output: Contribution to journalArticlepeer-review

27 Scopus citations


Aggregates consisting of nanometer sized primary particles are ubiquitous in the atmosphere. Sources of these particles such as combustion and nanoparticle manufacturing require control by filtration. To further investigate how loading processes are impacted by aggregate characteristics, we evaluated the loading of diesel particulate matter (DPM) on membrane filters at ambient temperature. Experimental results indicated that the filtration face velocity, engine load, and the usage of a catalytic stripper (CS) impact the characteristics of the resulting aggregate deposit or "cake". Mode aggregate size and primary particle size were slightly higher at 75% load (63.8 and 44.9. nm, respectively) compared to 37.5% load (57.3 and 40.9. nm, respectively). In-situ direct measurements of cake thickness enabled calculations of the porosity of the aggregate cakes which indicated that porosity varied between 0.93 and 0.97. The CS removed condensed semi-volatile organic material from the aggregates, which in turn impacted the calculation of porosity. Modeling based on Endo, Chen and Pui (Powder Technology, 1998, 98, 241-249) [1] of the pressure drop was performed based on the observation that cakes formed by the aggregates could be regarded as formed by a uniform collection of primary particles and once deposited, the aggregates were indistinguishable. The sensitivity of this model to various analytical expressions for the void function depending on the porosity was investigated. Results showed that available expressions vary greatly, although some of them provided satisfactory fitting for the experimental data.

Original languageEnglish (US)
Pages (from-to)244-251
Number of pages8
JournalPowder Technology
StatePublished - Jun 2013

Bibliographical note

Funding Information:
The work was partially supported by the grant “Particulate Matter and Gas Phase Emission Measurement of Aircraft Engine Exhaust” by the + HUMMEL, GMBH, MSP Corp., Samsung Electronics Co., Ltd, Shigematsu Works Co., Ltd, TSI Inc., and W. L. Gore & Associates, Inc. and affiliate member NIOSH. Swiss Federal Office of Civil Aviation and the grant “Real-time Measurement of Agglomerated or Aggregated Airborne Nanoparticles Released from a Manufacturing Process and their Transport Characteristics” by US National Science Foundation with award ID: 0646236 . The authors thank the support of the members of the Center for Filtration Research: 3M, Boeing Commercial Airplanes, Cummins Filtration, Donaldson Co., Inc., Entegris, Inc., Hollingsworth & Vose Co., MANN


  • Catalytic stripper
  • Filter loading
  • PTFE filter
  • Porosity
  • Pressure drop


Dive into the research topics of 'Microstructural and loading characteristics of diesel aggregate cakes'. Together they form a unique fingerprint.

Cite this