A constant volume diesel spray combustion facility and the corresponding experimental diagnostics

Abstract

A facility was built to examine the diesel spray/combustion process. The facility centers around a constant volume vessel, which consists of a visible and infrared optically accessible cold-wall, heated-interior pressure vessel coupled to an injection system. The combustion vessel is capable of operation at 50 atm and 1000 K ͑before injection͒, was used to simulate preinjection diesel in-cylinder conditions, and was coupled to a repeatable ͑for each fuel type͒, single shot, high pressure, metering fuel injection system. A number of experimental diagnostics have been applied to the facility and will be briefly discussed and examples of typical results offered. These diagnostics include: extractive post-combustion gas concentration experiments, droplet sizing measurements, and emission/absorption temperature measurements. Results from this facility capture the critical aspects of diesel spray combustion but do not include the change in pressure associated with heat release in a small volume and volume expansion due to piston motion.

A Comparison of Single Shot Diesel Spray Combustion Emissions With Trends Predicted by a Conceptual Model

“…Further details of the experimental system and gas extraction can be found in the literature. (Labs et al, 2005) Important features of this system for the work discussed in this article are:…”

Diesel spray mixing limited vaporization with non-ideal and multi-component fuel thermophysical property effects

“…There are two main types of constant volume combustion vessels, heated vessels and pre-combustion vessels, for reaching ambient conditions. Heated combustion vessels have lower temperature and pressure limits compared to that of the pre-combustion vessels and have reduced applicability for future advanced combustion strategies since they are constrained by electric heater capabilities (Fujimoto and Sato 1979;Baert 1989;Labs et al 2005;Nishida et al 2007;Baert et al 2008;Pawlowski et al 2008). Pre-combustion vessels can achieve a wider range of conditions, enabling study at conditions not currently attainable or used in existing technology engines, permitting the study of advanced combustion strategies.…”

“…Typically preburn procedures are required to provide the thermodynamic state for diesel engine study which produces reactive minor species, and engine geometry and cycling rates cannot be replicated for direct comparisons (Oren et al 1984). An additional application of these vessels is that their conditions are well-controlled, and wellcharacterized, providing use for Computational Fluid Dynamics (CFD) modeling including development, validation and calibration, which in synergy with experimental engine studies, can provide insight and knowledge for diesel engine advancements (Hurn and Hughes 1951;Reitz and Rutland 1995;Labs et al 2005;Vishwanathan et al 2009).…”

“…Additionally these results provide excellent datasets for computational fluid dynamics (CFD) model development, calibration, and validation (Reitz and Rutland 1995;Vishwanathan et al 2009). Combined numerical modeling and combustion vessel (CV) experimental studies have continuously provided significant insight and knowledge for the sustained advancement of diesel engines (Hurn and Hughes 1951;Labs et al 2005).…”

“…To create the range of in-cylinder temperatures (750 to 1300 K) that are generated by compression, boosting, and exhaust gas recirculation (EGR) in a diesel engine before spray injection and combustion, the gases in the apparatus must be preheated by some means. Electrical heating is applied in many systems (Fujimoto and Sato 1979;Baert 1989;Labs et al 2005;Nishida et al 2007;Pawlowski et al 2008). However, typically these systems have a limited temperature range, and it is difficult to match the composition of in-cylinder gases found in an engine.…”