Shivam S. Verma

Thermal & Fluid Engineering

My dissertation measures how fast gases cross an air–water interface and how dissolved salt, sugar and surfactants change that rate. Surface-tension gradients are the common thread through my work. The same Marangoni stresses act on a raindrop hitting the ocean, a heated plate in a coolant bath, and a drop full of particles in an electric field.

Dissertation Gas transfer experiments · PLIF · 2-D CFD in MATLAB

Gas transfer across the air–water interface and its dependence on dissolved solutes

In more than 500 experiments in sealed 3 to 4.5 L chambers, I measure how fast CO₂, O₂ and air dissolve into water while varying salinity up to 35 g/kg, sucrose up to 200 g/kg, surfactant up to 100 mg/kg, stirring in the water up to about 1,000 rpm, and five fan settings in the air. A sensor tracks the CO₂ concentration in the headspace, and a stagnant-film analysis turns its decay into a transfer velocity; across the program these span 0.5 to 20 cm/h. Because the measurement is sensitive to the room, every run starts with a stabilization dwell that holds temperature within ±0.1 °C and humidity at 95%. In fresh water, surfactant roughly halves the CO₂ transfer velocity, from 7.2 to 3.4 cm/h.

A 2-D Navier–Stokes model in MATLAB shows how dissolved CO₂, which makes the surface water heavier, turns the surface layer unstable and sinks in plumes; the Rayleigh number sets the onset.

Manuscript in preparation · APS DFD 2024 · APS March Meeting 2026 · Full write-up

Published 2023 PIV · High-speed imaging · PIVlab

Marangoni flow induced by a raindrop impact

A raindrop changes the salt and surfactant concentration where it lands, and the resulting surface-tension gradient drives flow along the surface. Dropping 3.4 mm drops from 5 to 60 cm (impact speeds of 0.9 to 2.9 m/s, Weber numbers of 40 to 385), we showed that the direction and strength of this flow depend on the Weber number and on the salt and surfactant Marangoni numbers. Salt made the outward surface flow last about seven times longer than in fresh water; surfactant reversed it into a downward jet and halved the particle-free region, from 30.7 to 15.2 mm.

Mechanics Research Communications 133, 104187 · Full write-up

In preparation Ansys Fluent VOF · PIV · Thermal imaging

Marangoni-enhanced heat transfer and bath cooling

CFD of flows driven by temperature-dependent surface tension. A heated plate submerged in water warms the free surface above it, and the surface-tension gradient pulls fluid along the surface and adds to natural convection, a mechanism relevant to bath (immersion) cooling of electronic components. I model it with the volume-of-fluid method in Ansys Fluent and validate the model with PIV and thermal imaging. Marangoni-driven flow raised the heat-transfer rate by 14% over buoyancy-driven convection alone.

APS DFD 2023 AC fields · 1 kHz–1 GHz · up to 5 kV

Particles in drops and vesicles under AC electric fields

Manipulating 16–20 µm glass particles inside water microdroplets and giant unilamellar vesicles suspended in dielectric media. Larger drops deformed much more than microdroplets, where surface tension dominates, while vesicles of similar size barely deformed. Inside drops the particles formed chains through dipolar interactions; inside vesicles they formed chains attached to the walls. Raising the field further makes a drop tip-stream and eject the collected particles, leaving it clean.

APS DFD 2023 · Full write-up

Master’s thesis OriginPro · MATLAB · COMSOL · NIST data

Thermal conductivity of supercritical oxygen

A six-term correlation for the thermal conductivity of supercritical oxygen on its critical isobar, from the critical point (154.58 K) to 500 K. Using density alongside temperature lets it follow the sharp peak at the critical point: against 3,455 NIST points the average error is 0.25%, and a neural network trained on the same data serves as an independent check. It extends my M.Tech work, which developed correlations for density, viscosity, thermal conductivity and specific heat along four isobars to judge supercritical oxygen as a coolant for superconducting motors.

Manuscript in preparation · Full write-up

Engineering projects

Thermal design work, test rigs, and tools I have built, from chip cooling to a hybrid vehicle prototype.

Conjugate heat transfer CFD · Liquid cooling

Chip-level cold plate design

A water-cooled copper microchannel cold plate for a 20 × 20 mm die dissipating 400 W, a heat flux of 100 W/cm², with 0.3 × 2.0 mm channels sized from developing-flow correlations. Across 14 three-dimensional conjugate heat transfer runs from 0.2 to 2.0 L/min, a serpentine layout ran the die 3 to 6 K cooler than straight channels at the same flow and cut its temperature spread by 57%. The price: 17 to 31 times the pressure drop, and about 12 times the pumping power to hold the die at 60 °C.

The model matches the Shah and London friction factor within 1.9% on the finest mesh, and a three-level mesh study gives grid convergence indices of 3% or less.

• 400 Won a 20 × 20 mm die
• −6 Kpeak temperature
• −57%die temperature spread
• 12×pumping power at 60 °C

Full write-up

Straight · 53.4 °C Serpentine · 48.3 °C

Python · OpenCV · PyQt6

Optical-flow velocimetry tool

SmokeVel, a desktop tool that turns an ordinary smoke video into a velocity field with Farnebäck dense optical flow, for measurements where a full PIV setup is not practical. It overlays speed maps, probes points, and averages profiles along an axis. Tested on the jet from a 1 inch fan filmed at 60 fps.

Full write-up

Thermoelectric control · LabVIEW · Shadowgraphy

Temperature-controlled contact-angle rig

A thermoelectric stage built from a TEC module on a fan-cooled heat sink, a copper heat spreader, and a surface thermocouple logged in LabVIEW. It holds aluminum, glass and Teflon substrates anywhere from about 12 to 74 °C while a camera records water drops in silhouette, across 20 test cases.

Full write-up

Team lead · Ansys · MATLAB · FMEA · Auto Expo 2014

Split hybrid electric vehicle prototype

Led the student team, coordinating its mechanical and electrical sub-teams, that turned a compact petrol hatchback into a hybrid with separate engine and electric-motor powertrains, exhibited at Auto Expo 2014 in New Delhi. I sized the 10 kW motor with a MATLAB vehicle-dynamics model, designed and pressure-tested the battery water-cooling loop, used Ansys to optimize the transmission and coolant flow rate, and ran the FMEA. I also wrote the fabrication drawings, vendor specifications, BOMs and assembly procedures, and bought parts within budget and schedule.

Full write-up

Methods and software

Publications and talks

Teaching and mentoring

Supervised student projects

• 15⁺undergraduate capstone projects
• 2master’s dissertations

Three of the projects I supervised:

Education and positions

1. Sep 2021 – May 2027 (expected)

   PhD, Mechanical Engineering · Graduate Teaching and Research Assistant

   New Jersey Institute of Technology, Newark, NJ

   Micro Flow Control Group, Department of Mechanical and Industrial Engineering. Advised by Prof. Pushpendra Singh and Prof. Ian S. Fischer. Dissertation on gas transfer across air–water interfaces and Marangoni-driven surface flows. Courses include Dynamics of Incompressible Fluids and Continuum Mechanics.

   • Designed and built test rigs for heat and mass transfer and interfacial flow studies, and ran more than 500 experiments, tightening repeatability through controlled test conditions.
   • Measured temperature, pressure, humidity, gas concentration and dissolved oxygen, and recorded flow fields with PIV, PLIF, thermal imaging and high-speed imaging.
   • Coordinate about $45,000 a year in lab purchasing: equipment specifications, vendor quotations and negotiation, supplier recommendations and order tracking, so rigs are built on budget and on time.
   • Maintain, calibrate and troubleshoot lab equipment, keep the inventory, and train new researchers on safe use.
2. Jul 2015 – Jun 2021

   Assistant Professor, Mechanical Engineering

   Lovely Professional University, Punjab, India

   Taught thermodynamics, heat transfer, fluid mechanics, refrigeration and air conditioning, and applied thermal engineering, with an average evaluation of 4.87 out of 5. Supervised more than 15 capstone projects and two master's dissertations, and advised the SAE BAJA team.

3. 2010 – 2015

   B.Tech and M.Tech (dual degree), Mechanical Engineering

   Lovely Professional University, Punjab, India

   M.Tech thesis on thermophysical property correlations for supercritical oxygen in HTS motor cooling, advised by Dr. Raja Sekhar Dondapati and accepted for a talk at ICEC 2014. Graduate courses in advanced thermodynamics, advanced fluid mechanics, advanced heat and mass transfer, RAC system design, and thermal system simulation and design. Led the split hybrid electric vehicle prototype shown at Auto Expo 2014.

4. Professional development

   NSF I-Corps Propel(us) program

   Conducted 30 customer-discovery interviews on the market need for a magnetorheological-fluid vibration absorber, and used the findings to judge product–market fit and refine the application.