Embedded Files
Overview
My research focuses on studying fundamental processes such as fuel atomization, air–fuel mixing, and combustion behavior in low-temperature combustion (LTC) regimes, achieved using low-reactivity fuels such as alcohols and green naphtha. To investigate these phenomena, I apply a range of optical diagnostic techniques that enable non-intrusive, high-resolution measurements, offering deeper insight into complex in-cylinder processes using an optical combustion chamber.
I developed and implemented advanced imaging techniques, including:
Schlieren imaging – for visualizing vapor boundaries of evaporating and gaseous sprays
SLIPI-enhanced LIF–Mie imaging – for planar Sauter Mean Diameter (SMD) distribution
Color ratio pyrometry – for flame temperature measurements
Light extinction imaging – for soot quantification (still developing setup)
Diffused backlit imaging (DBI) – for capturing liquid spray boundaries
In addition to optical diagnostics, I have hands-on experience with:
Phase Doppler Interferometry (PDI) – for droplet sizing and velocity measurements
Pulsed Nd:YAG lasers – for laser-based diagnostics and imaging synchronization
LabVIEW – for experimental control and data acquisition
DAQ systems – including high-speed, multi-channel instrumentation setups
MATLAB – for image processing, data analysis, and visualization
Converge CFD - For 3D Simulation of sprays and flames
Low Temperature Combustion
My research explores Gasoline Compression Ignition (GCI) as a pathway to achieve Low-Temperature Combustion (LTC), which reduces soot and NOx emissions by forming a lean, well-mixed fuel–air mixture prior to ignition. Using low-reactivity fuels like alcohols and green naphtha, GCI enables delayed autoignition and rapid heat release, improving both emissions and thermal efficiency. I study these processes under simulated engine conditions using a Constant Volume Combustion Chamber (CVCC) integrated with optical diagnostics.
Constant Volume Combustion Chamber
To simulate realistic engine-relevant conditions under controlled laboratory settings, I use a Constant Volume Combustion Chamber (CVCC) equipped with high-speed optical diagnostics. The CVCC generates the required high ambient pressure and temperature conditions through pre-combustion of a lean fuel–air mixture, prepared using high-pressure gas cylinders.
The desired mixture composition is achieved by controlling the partial pressures of each constituent gas, ensuring precise stoichiometry. Once the chamber reaches a uniform mixture, premixed combustion is initiated by a spark plug, leading to a rapid pressure rise. As the pressure decays and stabilises at the desired level, the fuel spray under investigation is injected into the chamber.
The CVCC features two quartz optical windows, allowing 90 mm optical access for the application of optical diagnostics.
Some Optical Techniques:
The Schlieren technique operates on the principle of light refraction due to variations in fluid density. When a light beam passes through the test section, regions of higher density cause the beam to deflect, resulting in a shifted image at the image plane. This technique effectively captures the first spatial derivative of fluid density by using a knife-edge positioned at the focal point of the imaging system. The placement of the knife-edge significantly influences image contrast and is typically aligned parallel to the nozzle axis, enabling clear visualization of density gradients along the spray width. I am using this technique to visualize the vapor spray boundary and also the temperature flame.
Structured Laser Illumination Planar Imaging (SLIPI) with LIF/Mie is an advanced optical technique used to obtain accurate, spatially-resolved measurements of droplet size distribution (Sauter Mean Diameter, SMD) in high-pressure fuel sprays. By combining fluorescence (LIF) and light scattering (Mie) signals under structured laser illumination, SLIPI suppresses multiply scattered light, enabling precise quantification of SMD which is critical for optimizing atomization and mixing in compression ignition (CI) engine.
Page updated
Google Sites
Report abuse