A REDESIGN OF THE EXHAUST AND GAS SAMPLING SYSTEM OF THE FIRE PROPAGATION APPARATUS

Standard bench scale fire apparatuses are useful tools to perform repeatable and reproducible firetests that acquire key fire properties, such as heat release rate and time to ignition, for materials in a cost-effective manner. The Fire Propagation Apparatus (FPA) is one of the only standard bench scale apparatuses that has the ability to acquire these key fire properties in a controlled environment setting. However, the design of the apparatus is quite complex. In this work, the exhaust and gas sampling system designs were redesigned and constructed to increase modularity and manufacturability, adapt to the University of Maryland’s Department of Fire Protection Engineering laboratory settings, and provide greater ease for the end user operations. After the construction of the FPA systems, tests were conducted to verify the accuracy of the measurement devices. Equations for the calculation of heat release rate from FPA sensor data were derived and used for a series of combustion experiments. These equations were compared to the ones provided in the standard to gain insight on their systematic differences

Evaluation of exhaust flowrate measurement techniques for a mobile emissions monitoring system

West Virginia University designed and developed Mobile Emissions Monitoring System (MEMS) for the six settling Heavy-Duty Diesel Engine (S-HDDE) manufacturers. The MEMS measures emissions concentrations while operating in a real world environment. The best method for measuring the emissions concentrations was found to be through raw exhaust sampling. In order to properly calculate the emissions concentrations the total exhaust flowrate through the engine must be determined. The devices evaluated were an Annubar, an Accutube, a hot film anemometer, a Pitot static tube, a venturi, and a vortex shedder.;The evaluation of the devices was broken down into two parts, the first part included cold bench testing and the second engine testing. The venturi was found to be the best flow device for a MEMS because of the increased flow range over the vortex shedder and was well suited for the environment of compression ignition exhaust streams

Flow Measurement of Wet CO2 Using an Averaging Pitot Tube and Coriolis Mass Flowmeters

The flow measurement of wet-gas is an active field with extensive research background that remains a modern-day challenge. The implication of wet-gas flow conditions is no different in Carbon Capture and Storage (CCS) pipelines. The associated complex flow regime with wet-gas flow makes it difficult to accurately meter the flow rate of the gas phase. Some conventional single-phase flowmeters like the Coriolis, Orifice plate, Ultrasonic, V-Cone, Venturi and Vortex have been tested for this application, usually accompanied with special recommendations. Often, a correlation equation valid within a certain range of specific conditions is required to correct the response of the flowmeter. This paper presents investigations into the suitability and performance of one of the most advanced averaging pitot tubes for the flow measurement of wet CO2 gas. The averaging pitot tube with flow conditioning wing geometry (APT-FCW) was studied and experimentally assessed in earlier work for the flow measurement of pure and dry CO2 within an error of ±1%. Under wet-gas conditions, however, the APT-FCW sensor is found to give an error of up to ±25% and within ±1.5% after appropriate correcting solutions are applied for a liquid fraction of up to 20%

Comparison of a Work-Based Window Method to NTE Method for Reporting In-Use Emissions

Heavy-duty on-road diesel engines currently sold in the United States are subjected to emission certification over the Federal Test Procedure and Supplemental Emissions Test in an engine test cell as well as in-use testing in real world environments using portable emissions measurement systems (PEMS). The current method for analyzing in-use emissions is based on the Not-To-Exceed (NTE) region of engine operation. With this method, emissions are reported only when the engine is operating in the NTE region for a minimum of thirty seconds. The downfall to this method is that any engine operation outside of this region is neglected. An alternative method for measuring in-use emissions is based on a work approach previously proposed by Shade. This method integrates power produced by the engine over time to create work windows; the integration duration can be defined using a pre-specified work level. One such work level could be the work that the engine was exercised over during the Federal Test Procedure. The emissions produced during this window are then summed and divided by the work to produce brake specific emission levels for each window. By basing this analysis on work produced by the engine instead of time an engine spends in a certain region of operation, almost no point of engine operation is neglected and the majority of all emissions produced during the test are accounted for.;A study using in-use compliance data from seven vehicles representing diverse vocations was used to compare the currently implemented NTE method of in-use emissions measurement and a proposed work-based window method for measuring brake specific emissions of CO, CO2, NOx, THC, and PM emissions. Analysis of this data showed that without any exclusions applied to either method, the work-window method resulted in an average percent difference of 162% higher CO, 12% higher CO2, 94% higher NOx, and 186% higher THC emissions when compared to the average NTE results. Average PM results from the work-window method, however, showed a 122% lower level than the NTE method. Due to limitations associated with the NTE method, it was determined that the work-based window method may still provide better representation of actual in-use emissions despite the higher calculated brake specific emission levels

Pollution Reduction Technology Program for Small Jet Aircraft Engines, Phase 2

A series of iterative combustor pressure rig tests were conducted on two combustor concepts applied to the AiResearch TFE731-2 turbofan engine combustion system for the purpose of optimizing combustor performance and operating characteristics consistant with low emissions. The two concepts were an axial air-assisted airblast fuel injection configuration with variable-geometry air swirlers and a staged premix/prevaporization configuration. The iterative rig testing and modification sequence on both concepts was intended to provide operational compatibility with the engine and determine one concept for further evaluation in a TFE731-2 engine

Pollution reduction technology program small jet aircraft engines, phase 3

A series of Model TFE731-2 engine tests were conducted with the Concept 2 variable geometry airblast fuel injector combustion system installed. The engine was tested to: (1) establish the emission levels over the selected points which comprise the Environmental Protection Agency Landing-Takeoff Cycle; (2) determine engine performance with the combustion system; and (3) evaulate the engine acceleration/deceleration characteristics. The hydrocarbon (HC), carbon monoxide (CO), and smoke goals were met. Oxides of nitrogen (NOx) were above the goal for the same configuration that met the other pollutant goals. The engine and combustor performance, as well as acceleration/deceleration characteristics, were acceptable. The Concept 3 staged combustor system was refined from earlier phase development and subjected to further rig refinement testing. The concept met all of the emissions goals

In Service Monitoring based on PEMS of NRE engines under 19kW

This report summarizes the results of a pilot program dedicated to develop a procedure for the In Service Monitoring of NRMM Small Compressed Ignition engines (categories NRE-v-1, NRE-v-2, NRE-c-1, NRE-c-2) based on Portable Emission Measurement System (PEMS). The tests took place between January 2018 and February 2019. The work addresses how to mount the measurement equipment on board of such machinery and the accuracy and precision of the exhaust gaseous pollutant emission measurements using PEMS. Compared to a standard test performed in an engine test cell (VELA_6 and at OEM facilities) the concentration measurements accuracy and precision was within 10%. In service tests showed that the results were stable and reproducible.JRC.C.4-Sustainable Transpor

Development of a Reference Dataset to Evaluate PEMS Post-Processing Software

Since the implementation of in-use emissions standards, an outcome of the consent decree between heavy-duty diesel engine manufacturers and the Environmental Protection Agency (EPA), there has been an increased interest in the research and development of portable emissions measurement systems (PEMS) that are capable of analyzing exhaust emissions continuously while a vehicle or equipment powered by an internal combustion engine is performing its intended vocation. Ultimately for an engine to pass in-use emissions requirements, the brake specific emissions of regulated pollutants measured over valid Not-to-Exceed (NTE) events must be less than or equal to 1.25 or 1.5 times the engine emission certification standards, based on the engine model year (MY), plus an additional margin known as in-use measurement allowance. The vehicle has to satisfy the in-use emissions standard for 90% of the NTE events provided the brake specific emissions over the rest of the events are less than two times the certification level to comply with in-use emission regulations.;As in-use emissions measurement and regulation together form a requirement since 2004 for certification of engines, it is imperative to develop procedures of oversight similar to ones that exist for laboratory-based engine certification. Therefore, a reference data set that incorporates all the in-use emissions regulations used to quantify the measured emissions over an NTE event, including the conditions used to validate an NTE event is developed in the direction of providing a means to validate commercial PEMS data analysis software.;A reference data set was designed and used to evaluate the post-processing software of two commercial PEMS devices. A black box testing methodology was implemented to evaluate the performance of the post-processing software. Specifically, the input data set was developed to execute different sections of the program based on logical conditions required to branch into a particular section therefore verifying the truth in executing a logical condition and the interpretation of in-use emissions regulation. Also, the brake specific emissions results to be expected from the given input data set were known a priori to verify the accuracy of the equations used in calculating the final emissions results. The dataset was also used to evaluate PEMS data post-processing software developed at WVU.;The test results indicated that definition of NTE emissions performance was not in agreement for the post-processing software evaluated. Being that compliance is required for manufacturers to sell engines without penalty, it is critical that the metric by which compliance is assessed must be accurate and robust. As such, the reference data set developed will serve in identifying interpretation errors of in-use emissions regulations as well as calculation error and reduce the chances of triggering false positives and negatives that could prove costly to engine manufacturers as well as air quality regulating agencies. This reference data set will also serve in effective implementation of any modification of existing or additional new in-use emissions compliance requirements and verify it across different in-use emissions data post-processing software supplied by PEMS manufacturers and developed in-house. Test results showed that PEMS post-processors outcome were not in agreement with expected total number of 166 NTE events as the in-house, PEMS A and PEMS B returned 216, 288 and 190 NTE events respectively. The reference dataset was instrumental in identifying interpretation error in the in-house data post-processor leading to a revised version of the software that matched the expected results