Dynamic Compressor Mass Flow Interpolation for Surge and Choke Control
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Solution Overview
Problem
Dynamic compressors, such as centrifugal compressors, face inefficiencies and instability issues like choked flow and surge, which can damage the machine, but determining mass flow rate is costly with traditional instrumentation.
Innovation Solution
A controller with a memory storing a map of predetermined operating points, including mass flow data, calculates real-time mass flow without additional sensors by interpolating from these points, using linear or envelope interpolation methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional mass flow sensors are installed to measure mass flow rate, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent creates a virtual copy of the mass flow sensor by generating a lookup table with predetermined operating points that include mass flow values. This software-based model replicates the function of a physical sensor without requiring actual sensor hardware, thereby eliminating the need for expensive mass flow sensors while maintaining measurement capability through interpolation of the lookup table data
Solution Approach 2:
The patent replaces the mechanical/physical mass flow sensing system with a computational system. Instead of using physical sensors to directly measure mass flow, the system uses a processor to interpolate mass flow values from a lookup table based on other measurable parameters (such as speed and pressure), substituting mechanical measurement with computational calculation
2Reliability
If real-time mass flow data is obtained through additional instrumentation, then reliability is improved, but cost increases
Solution Approach 1:
The patent performs preliminary action by pre-calculating and storing mass flow values for multiple predetermined operating points in a lookup table during system initialization or offline processing. This advance preparation allows the system to quickly determine mass flow during real-time operation simply by interpolating from the pre-computed data, eliminating the need for real-time sensor measurement while maintaining reliability
Solution Approach 2:
The patent creates a virtual copy of the mass flow sensor by generating a lookup table with predetermined operating points that include mass flow values. This software-based model replicates the function of a physical sensor without requiring actual sensor hardware, thereby eliminating the need for expensive mass flow sensors while maintaining measurement capability through interpolation of the lookup table data
3Device complexity
If the compressor operates without real-time mass flow monitoring, then device complexity is reduced, but the compressor may operate in inefficient or unstable regions
Solution Approach 1:
The patent implements self-service by enabling the control system to autonomously determine mass flow values through interpolation of a lookup table without requiring external sensor input. The system uses existing measurements (speed, pressure) and pre-computed data to self-calculate mass flow, providing itself with the monitoring capability it would otherwise need expensive sensors for, thereby maintaining reliability while minimizing complexity
Data Source
AI summary
A system includes a dynamic compressor to compress a working fluid and a controller. The controller is connected to the dynamic compressor and includes a processor and a memory. The memory stores a map of predetermined operating points of the dynamic compressor, each predetermined operating point including a mass flow of the compressor at that predetermined operating point. The memory stores instructions that program the processor to operate the dynamic compressor to compress the working fluid and determine a current operating point of the compressor. The instructions program the processor to calculate the mass flow for the current operating point from the map of the plurality of predetermined operating points. The instructions further program the processor to continue to operate the dynamic compressor to compress the working fluid based at least in part on the calculated mass flow for the current operating point.