ASHRAE RP-1800: Investigation of the effect of oil on spray evaporation of Low-GWP refrigerantsSpray evaporators are the best replacement for conventional flooded-type shell and tube heat exchangers. Low refrigerant charge and compact size make it an ideal candidate. However, lubricant oil in these heat exchangers may cause adverse effects on their heat transfer performance, and it was not studied well. This ASHRAE-sponsored research investigates the oil effect on L-GWP refrigerants during spray evaporation. • Designed and executed the experiments in pressurized flow loops. • Implemented a two-stage oil separation process, reducing the oil recovery time by 50%. • Designed and fabricated the sampler to measure the oil concentration ratio (OCR) in the system.ASHRAE RP-1683: Finding two-phase pressure drop of Ammonia in U-bendsU-bends are found very often in refrigeration and air-conditioning systems. The presence of the U-bend causes a change in the flow pattern in its vicinity, and it is more complex in two-phase flow. Therefore this is a crucial part of optimizing heat exchanger design. This ASHRAE-sponsored research investigates the two-phase flow pressure drop Ammonia in U-bend. • Designed and constructed the test setup to measure the liquid + vapor (Two-phase) pressure drop of Ammonia in U-bends. • Performed shakedown tests with R134a and R1233zd(E) to measure the U-bend pressure drop.

Pendant droplet evaporation induced external flow• Developed a numerical model to predict the evaporation-induced flow under a pendant droplet with the aid of commercial CFD package COMSOL. • Constructed test setup and carried out experiments to visualize the flow under pendant droplet by forming using particle image velocimetry (PIV).• Post-processing of the images was carried out in customized MATLAB code.Studies on fluidized bed reactor to process iron ore• Implemented shrinking core model to predict the reduction time with respect to the reaction of reduction of iron ore using MATLAB.• Developed a numerical model to predict the fluid flow inside a cyclone separator using the DPM-CFD approach using a commercial CFD package Ansys Fluent.• Assisted in a lab scale test setup of a fluidized bed reactor to carry out the experiments.

Waste heat recovery from PAFC and HT-PEM fuel cells• Involved in a project aims to recover waste heat from PEM and PAFC fuel cell.• Performed a thermodynamic and economic analysis of various cooling systems, mainly Ejector cum vapor compression hybrid system, LiBr-water absorption systemand Ammonia-Water absorption system using Engineering Equation Solver (EES).

M.S. Thesis Project: Falling film evaporation of water on corrugated conduits• Designed and constructed an innovative corrugated plate surface for desalination application.• Developed a suitable numerical model to predict the fluid flow and heat transfer characteristics of falling film evaporation on a vertical corrugated conduit with an appropriate phase change model.• Carried out the experimental studies on a falling film evaporator and studied heat and mass transfer characteristics at different operating conditions.• Studied the influence of porous thermal spray metallic coating on corrugated conduit surface for heat transfer enhancement with CFD and experiment analysis.Teaching Assistant, Thermodynamics• Created comprehensive solutions to assignments for a class of 60 students.• Conducted tutoring sessions with undergraduate students needing additional assistance.