Dimitris Assanis

• Doctor of Philosophy
• Professor (Assistant) at Stony Brook University

In the face of new engine research challenges, legacy hardware and once state-of-the-art assumptions may become less relevant, especially those made due to the computational limitations of the hardware at the time of initial development. Such legacy elements can potentially limit the effectiveness of accurately describing key parameters or metrics...

A holistic literature review of 399 articles is presented on hybrid solid oxide fuel cell (SOFC) systems and taxonomized through a unique classification methodology that considers primary energy sources, component configurations, system outputs and relevant analysis. In the reviewed research articles, primarily four different types of technologies...

Existing engine facilities often build upon legacy hardware and assumptions that were once state-of-the-art, but have since become less relevant or even outdated in the face of new research challenges facing the community today. Often, assumptions and simplifications to experimentation or analysis, once necessary to be made due to the computational...

There is growing interest in ammonia, NH3, as a zero-carbon fuel for use in transportation as part of broader decarbonization efforts. Ammonia has several advantages as an alternative fuel, including an existing global infrastructure and the ability to be stored as a liquid at room temperature and moderate pressures, thereby increasing its volumetr...

In this study, a computational fluid dynamics (CFD) model of a single-cylinder compression ignition engine is developed and validated under motoring conditions. The engine used is the Ricardo Hydra engine at the Advanced Combustion and Energy Systems laboratory at Stony Brook University, which is highly instrumented to collect all data necessary fo...

With regulations imposing tighter restrictions on carbon emissions, it is crucial to explore the use of carbon-free fuels. Ammonia, NH3, is increasingly being perceived as a dominant hydrogen carrier candidate fuel due to its efficient hydrogen atom arrangement, ease of storage, and for already having an extensive transportation network as the seco...

Medium and heavy-duty (MHD) diesel engine applications are currently facing technical challenges in accomplishing decarbonization goals due to the lack of readily available technological solutions that can meet the large power density requirements needed. For example, while electrification may show promise for certain light-duty vehicle application...

The continued development of aftertreatment devices has been critical in reducing engine tailpipe emissions and meeting ever-evolving regulatory standards. Initial phases of catalytic aftertreatment device evaluation often occur at physically scaled-down conditions, typically using laboratory benchtop reactors to test synthesized catalysts that are...

While ammonia (NH3) and hydrogen (H2) are promising carbon-free fuels, there are significant challenges presented by their combustion properties. Blending them can help mitigate some of these issues; however, the fundamental behaviors of these blends need to be well understood. A constant volume combustion chamber (CVCC) is used to study the emissi...

div class="section abstract"> Design, testing, and implementation of new aftertreatment devices under various engine operating conditions is necessary to meet increasingly stringent regulatory mandates. One common aftertreatment device, the catalytic converter, is typically developed at a reduced scale and tested using predefined fluid compositions...

div class="section abstract"> This paper delves into the intricate realm of Formula 1 race car aerodynamics, focusing on the pivotal role played by floor flow structures in contemporary racing. The aerodynamic design of the floor of a Formula 1 car is a fundamental component that connects the flow structures from the front wing to the rear end of t...

Developing a sustainable alternative to diesel and gasoline is critical to mitigating climate change effects. Methane, the primary component of natural gas, presents itself as a successor to petroleum-based fuels. Compared to other hydrocarbons, methane (CH4) has the highest hydrogen to carbon ratio which means when combusted in an engine, fewer ca...

Finding alternatives to carbonaceous fuels has become a prime focus to support the global goal of decarbonizing the transportation sector. Hydrogen is a promising alternative fuel given that it is lightweight, and its combustion produces zero carbon dioxide. However, the absence of widespread dedicated hydrogen infrastructure for transportation, di...

Even though usage of hydrogen (H2) in the energy sector has gained a considerable amount of traction over the last decade, its high flame speed restricts its feasibility as a drop-in replacement for existing fuels in applications such as internal combustion engines and gas turbines. In order to address some potential issues, ammonia (NH3) can be us...

Finding fuels derived from renewable sources that can displace fossil fuels is crucial to fight climate change as drop-in replacement fuels can immediately leverage ubiquitous, existing energy conversion hardware such as the reciprocating-piston internal combustion engine. However, any replacement fuel must necessarily maintain or ideally exceed th...

Computational Fluid Dynamics (CFD) simulations have a great potential to guide the optimization of fuel stratification strategies for internal combustion engines, but well-validated spray models are required. In this study, we aim to understand the current capability of CFD simulations, under conditions representative of partially stratified advanc...

Advanced Low Temperature Combustion modes, such as the Sandia proposed Additive-Mixing Fuel Injection (AMFI), can unlock significant potential to boost fuel conversion efficiency and ultimately improve the energy conversion of internal combustion engines. This is a novel improved combustion process that is enabled by supplying small (<5%) variable...

Wiebe functions, analytical equations that estimate the fuel mass fraction burned (MFB) during combustion, have been effective at describing spark-ignition (SI) engine combustion using gasoline fuels. This study explores if the same methodology can be extended for SI combustion with syngas, a gaseous fuel mixture composed of H2, CO, and CO2, and an...

Many efforts have been made in recent years to find renewable replacements for fossil fuels that can reduce the carbon footprint without compromising combustion performance. Bio-blendstock oil developed from woody biomass using a reliable thermochemical conversion method known as catalytic fast pyrolysis (CFP), along with hydrotreating upgrading ha...

A closed-cycle computational model of a non-Wankel rotary engine was thoroughly investigated to achieve optimal efficiencies, in a multitude of loading conditions relevant to automotive and aeronautical applications. Computational fluid dynamics (CFD) modeling was conducted in CONVERGE CFD, targeting the operation of a single prechamber and downstr...

In the first quarter of 2020, SARs-CoV-2 (COVID-19) infections began to grow at an alarming rate despite drastic measures to reduce infection rates. Severe COVID-19 cases required mechanical ventilation, resulting in ventilator shortages worldwide. To address the ventilator shortages, the authors developed the CoreVent 2020, an emergency-use ventil...

Biomass catalytic fast pyrolysis (CFP) integrated with hydrotreating (HT) produces advanced biofuels that could be used as bio-blendstocks to improve the properties of petroleum diesel fuels and enhance their combustion in compression ignition engines. The biofuels produced by CFP and HT are rich in naphthenes (cycloalkanes) that could improve cold...

Reactivity controlled compression ignition (RCCI) combustion has previously been proposed as a method to achieve high fuel conversion efficiency and reduce engine emissions. A single-fuel RCCI combustion strategy can have decreased fuel system complexity by using a reformate fuel for port fuel injection and the parent fuel (diesel) for direct injec...

Solid oxide fuel cells (SOFCs) have been deployed in hybrid decentralized energy systems, in which they are directly coupled to internal combustion engines (ICEs). Prior research indicated that the anode tailgas exiting the SOFC stack should be additionally exploited due to its high energy value, with typical ICE operation favoring hybridization du...

Wiebe functions, analytical equations that estimate the fuel mass fraction burned (MFB) during combustion, have been effective at describing spark-ignition (SI) engine combustion using gasoline fuels. This study explores if the same methodology can be extended for SI combustion with syngas, a gaseous fuel mixture composed of H2, CO, and CO2, and an...

With the rise in wood stove use in recent years, a number of experimental research efforts have been undertaken with the objective of developing cleaner, and more efficient stove designs. However, numerical modeling of stoves is still in its nascent years, thus making it imperative to start adapting more mature computational techniques, established...

With the rise in wood stove use in recent years, a number of experimental research efforts have been undertaken with the objective of developing cleaner, and more efficient stove designs. However, numerical modeling of stoves is still in its nascent years, thus making it imperative to start adapting more mature computational techniques, established...

Solid oxide fuel cell – internal combustion engine (SOFC-ICE) hybrid systems are an attractive solution for electricity generation. The system can achieve up to 70% theoretical electric power conversion efficiency through energy cascading enabled by utilizing the anode off-gas from the SOFC as the fuel source for the ICE. Experimental investigation...

Urban intersections, merging roadways, roundabouts , and speed reduction zones along with the driver responses to various disturbances are the primary sources of bottlenecks in corridors that contribute to traffic congestion. The implementation of connected and automated technologies can enable a novel computational framework for real-time control...

Fuel lean combustion strategies are attractive methods to increase the thermal efficiency of gasoline, spark ignition, internal combustion engines, but engine design remains challenging due to the lean flammability limits of the fuel/air mixture. Turbulent jet ignition originating from a pre-chamber can help address mixture flammability limits by e...

Recent modifications to the University of Michigan rapid compression facility (UM RCF) were made to allow direct imaging of flame/autoignition interactions using compression to initiate autoignition chemistry and a spark plug to initiate simultaneous flame development. The experimental data in this study quantify the effects of spark-initiated flam...

Spark-assisted homogeneous charge compression ignition (HCCI) combustion may be a method to improve the operation of HCCI engines. In the current study, the impact of spark assist on the fundamental properties of ignition and combustion was investigated in a single cylinder, optically-accessible research engine. Early port fuel injection and air pr...

This study presents two new methods to rapidly analyze the ignition and combustion events recorded during in-cylinder high-speed imaging of homogeneous charge compression ignition (HCCI) and spark-assisted (SA) HCCI engine operation. Two categories of ignition have been observed during HCCI and SA HCCI: auto-ignition of parcels of fuel/air and igni...

High-speed imaging combined with the optical access provided by a research engine offer the ability to directly image and compare ignition and combustion phenomena of various fuels. Such data provide valuable insight into the physical and chemical mechanisms important in each system. In this study, crank-angle resolved imaging data were used to inv...

High-speed imaging combined with the optical access provided by a single-cylinder research engine offer the ability to directly study ignition and combustion phenomena. Such data provide valuable insight into the physical and chemical mechanisms important in advanced engine combustion strategies. In this study, crank-angle resolved chemiluminescenc...