Manish Chandra

• Inter Disciplinary Direct PhD in Engineering| Department of Applied Mechanics and Engineering Design.

I am working on development of optical based non-intrusive real time steam quality measurement system using absorption and scattering property of light.

• The objective of project as:
• We have built optical and conventional-based measurement setups for steam quality. Initially, Optical based measurement was based on broadband SLED source. We directly capture the absorption spectrum using an optical spectrum analyzer (OSA). The change in intensity at absorbing and non-absorbing water vapour wavelength can be directly inferred to dryness fraction. We have also built the LASER-based measurement system due to limitations on the SLED-based measurement. We have also derived the extinction-based mathematical expression for scattering and absorption by molecules simultaneously in real time for dryness fraction calculation using LASER. We have obtained preliminary results for dryness fraction using extinction and absorption at non-absorbing and absorbing water vapour wavelengths and validated them with calorimeter-based measurement. A wavelength modulation spectroscopy-based has been built for the measurement of water droplet concentration in steam to achieve low-concentration
• We were also involved in developing the Multi-Channel, Low-Cost Acoustic Emission Monitoring System. The main objective was to design, simulate and implement eight-channel interrogators for an acoustic emission monitoring system to simultaneously detect signals at various places. Fibre Bragg Grating (FBG) sensor is used to detect the low-level signal. The Dense Wavelength Division Multiplexing (DWDM) interferometer demodulates the wavelength shift information buried in the optical signals. The integrated sensor can detect fast-varying acoustic signals (100 kHz to 1MHz). The system has a measurement capability of up to100µɛwithan accuracy of 1µɛ.

• Documented procedures and results with high degree of accuracy and precision.
• Graded quizzes, tests, homework and projects to provide students with timely academic progress information and feedback when I was Teaching Assistant for 'Design of Experiments in fluid Mechanics'.
• Monitored student use of optical tools and equipment for safe and effective handling.

Generated grant proposals to gain funding for :

1. 'Development of Dust Monitoring System Using light Scattering Principle for Stack Monitoring', winning 20lac for EngSUI project.

2. 'Development of Dust Monitoring System Using Optical Scattering Principle for Stack Monitoring' winning 2 lac for Innovative Projects IITM (Nirmaan).

3. 'Customer discovery process' winning 2.5 lacs for GDC I-ncubate Cohort4 project.

• I was working on the project entitled “Tunable Diode Laser Absorption Spectroscopy (TDLAS) based Oxygen Sensor for On-board Inert Gas Generating System (OBIGGS)/ Aircraft Ullage Space of Fuel Tank”. This project aims to develop the Tunable Diode Laser Absorption Spectroscopy (TDLAS) based Oxygen sensor, which will monitor the oxygen concentration in the ullage space of an aircraft fuel tank. Since aircraft carry highly inflammable fuel on board, for propulsion, it becomes essential to restrict the oxygen concentration below a threshold value in the ullage space of a closed fuel tank to safeguard the aircraft from the risk of explosion. Hence, developing a sensitive, quick-response optical oxygen sensor for continuous monitoring of ullage space oxygen concentration is desired for enabling the appropriate inerting mechanism when required. TDLAS-based Oxygen Sensor is capable of low monitoring levels of Oxygen Concentration and is free of cross-interference from other gases. This development involves the concept validation using a bench model and the development of a portable sensor with integrated electronics. It utilizes the concept of Wavelength Modulation Spectroscopy for the detection of species/gas molecules. Phase Sensitive Detection (PSD) based Lock-In technique is used to find the required Harmonic signal (first and second) of Absorbance signal to determine Oxygen Concentration.
• My role in the development of the MIL-grade sensor project includes the following:

(I) Characterization of laser source parameters and Optimization of Tuning current, Injection current and modulation voltage to achieve suitable modulation index for maximum absorption signal.

(II) Oxygen Concentration measurements using the Bench top model involves calculating intensity modulation coefficient (i1, i2, φ1, φ2), ratio of different harmonics, Baseline measurement and measurement of Oxygen concentration.

(III) MATLAB Programming for Line Width, Oxygen Concentration measurement for low and high absorbance conditions using 2f/1f & 4f/1f method.

(IV) Design, Development and Testing of Laser Diode Driver (LDD), which includes Current Control Circuit, Temperature Control Circuit, Excess Current protection, Over Voltage protection circuit and Interfacing of LDD with the Microcontroller to make the whole circuit miniaturized and completely automated.

(V) Design, Development and Testing of Photo Receiver, Signal Conditioning Circuit and their Protection Circuit.

(VI) Simulation profile generation for Optical Absorption Signal using MATLAB

(VII) Development, Implementation, Testing and Optimization of Phase Sensitive Detection (PSD) based Digital Lock-In Amplifier in MATLAB.

(VIII) Implementation and validation of Digital low pass Filter in Microcontroller

(IX) Implementation and Validation of various signals (Sine, Triangular) and Phase Sensitive Detection (PSD) based Digital Lock-In Amplifier in Microcontroller.