MEMR Capacitance Tomography for High-Speed Flow Imaging
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Solution Overview
Problem
Existing Electrical Capacitance Tomography (ECT) methods, such as MECaP, are inadequate for capturing high-speed dynamics in time-sensitive applications due to limited measurement speed.
Innovation Solution
The Multiple-Excitation Multiple-Receiving (MEMR) method simultaneously excites multiple electrodes and receives signals from multiple electrodes, using unique excitation frequencies and lock-in amplifiers to isolate signals, allowing for increased measurement speed by reducing the number of steps required to complete a frame.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple excitation signals are applied to multiple electrodes simultaneously (MECaP method), then measurement speed is improved relative to traditional single excitation/single receiver systems, but the system can only read a single receiving electrode during each step, limiting further speed improvement
Solution Approach 1:
The electrode array is segmented into multiple receiving electrode groups, each group being read by dedicated receiving channels. This allows simultaneous reading of multiple receiving electrodes across different channels, breaking the single-receiving-electrode bottleneck of MECaP while maintaining modular system architecture
Solution Approach 2:
Each electrode in the array can function as either an excitation electrode or a receiving electrode depending on the measurement phase. The system universally utilizes all electrodes for both excitation and reception functions across different time steps, maximizing the utility of the electrode array and enabling multiple simultaneous measurements
2Speed
If traditional single excitation/single receiver system is used, then device complexity is minimized, but measurement speed is insufficient for capturing high-speed dynamics
Solution Approach 1:
The system implements continuous measurement cycles where multiple excitation electrodes and multiple receiving electrodes operate simultaneously in parallel. During each measurement step, multiple capacitance values are acquired at the same time, ensuring continuous data acquisition without sequential delays, thereby achieving high frame rates for capturing fast dynamics
Solution Approach 2:
The system transitions from single-dimensional sequential measurement (one excitation-one reception) to multi-dimensional parallel measurement by introducing multiple excitation electrodes and multiple receiving electrodes operating simultaneously. This dimensional expansion in the measurement space enables quadratic increase in measurement throughput
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
MEMR significantly improves the frame rate of ECT systems, increasing it by a factor of 9.3 compared to traditional methods and 2.3 compared to MECaP, enabling high-speed, non-intrusive monitoring of fast-changing processes like multi-phase flow and flame combustion with enhanced time resolution.
Implementation Method 1
using unique excitation frequencies and lock-in amplifiers to isolate signals
Implementation Method 2
measure the output current/voltage on another electrode (that forms the other plate of the capacitor), from which the capacitance is determined
Data Source
AI summary
A method for operating a sensor, including simultaneously exciting a first set of electrodes and sensing an output of each electrode of a second set of electrodes, storing output data corresponding to the output of each electrode of the second set of electrodes in a memory storage device, shifting at least one electrode from the first set of electrodes to the second set of electrodes and at least one electrode from the second set of electrodes to the first set of electrodes, and repeating the simultaneously exciting and sensing, the storing, and the shifting until an output data has been stored for each possible pair of electrodes in the first and second set of electrodes.