Date of Award

Spring 2019

Document Type


Degree Name

Master of Science (MS)


Mechanical Engineering

First Advisor

LEE, Chung Hoon

Second Advisor

Richie, James

Third Advisor

Singer, Simcha


This thesis presents flowmeter devices which can measure flowrate, pressure and temperature offlowing liquid samples using thermal measurement method. Typical thermal mass flowmeter usesthermal properties of materials to obtain flow features only for gases. We designed and fabricatedflowmeter devices with various functionalities such as: measuring properties of flowing liquid andidentifying the type of liquid samples.Thermal measurement methods using temperature sensor is a key of our flowmeter’s workingprinciple. The thermal mass flowmeter consists of a glass capillary, a tungsten wire heater, and aresistance temperature detector (RTD) sensor. The heater and sensors are integrated on the surface ofthe glass capillary. Noncontact flow measurement between sensor and liquid sample prevents flowdisturbance and corrosion of sensors. When robustness and sensitivity are required for flowmeasurement, the thermal mass time of flight (ToF) measurement method, along with its simplereadout, make it a great candidate for industrial and vehicle applications. The heat traveling timemeasurement is the method that measures the time of flight of thermal mass from heating site tosensing site. Depending on the flowrate of fluid and thermal diffusivity of the liquid sample, the heattraveling time differs.However, low response speed and low sensitivity characteristics are drawbacks of thermalmeasurement methods, which are influenced by thermal properties of materials and structural design.To increase sensitivity of our flowmeter, we fabricated and designed the device using differentcomponent variables such as: size and thickness of RTD sensors, heating element, and glass tubethickness. Also, the flowmeter introduced in this work has two different types based on their size andthey enable large flow range measurement. Micro-flowmeter can measure flowrate less than 100μl/min and macro-flowmeter measures flowrate from 1 to 10 gallon per minute (GPM) of deionized(DI) water.In this work, we used a number of techniques to increase the functionality of our device. Bypasssystem enables to measure high range of flowrate. Also, we designed gravity-driven flowratecalibration system to generate accurate flowrates. Moreover, we developed flowrate monitoringsystem to improve the performance of calibration system.

Included in

Engineering Commons