Plate-fin Heat Exchanger Gas Flow Resistance Characteristics Of The Study Of The Test System

Plate-fin heat exchanger is one kind of the compact, light weight and high efficiency heat exchanger, which has been widely used in the field of petrochemical, chemical, energy, power, air separation, vehicle shipping, refrigeration air-conditioning and so on. Heat exchanger flow characteristics have a direct effect of heat transfer. At present in the heat exchanger air resistance characteristics measurement, some companies still use orifice and valve to measure the airflow. This method looks simple but requires a lot of skill. Because it is manual operate. So the accuracy of detection data is difficult to be ensured and experiment efficiency is low. Because of the limitations exist in the air-resistance tester, author re-designed and developed a high-precision measurement and control system for plant-fin exchanger air resistance characteristics testing.In order to design and validate this new testing method used to test the air-resistance of the plate-fin heat exchanger, the main research work and conclusions of the paper are as follows:1. Author used the old measure system to obtain a large amount of original data, detailed analysis and pointed out the limitations of this system. Then author present a new measuring method which use the nozzle instead of throttling orifice way to precisely measure the airflow. By establishing an accurately controlled wind-tunnel testing system, detecting and monitoring the pressure drop, the inlet and outlet air temperatures, analyzing the exchanger's airflow and resistance, the exchanger air flow resistance characteristic curves can be automatically drawn.2. Plate-fin heat exchanger test stage consists of wind tunnel system, variable frequency control system, and control system. The structure of these three subsystems are detailed introduced in this paper and discussed the testing and calculation methods of the Experimental System with the theory of fluid mechanics principles.3. The modular programming and object-oriented programming are both employed. To analyze the demand of test and control system, Unified Modeling Language (UML) is utilized. The main model such as data acquisition and processing module, the user management module, history query module, instrument control and database module were describe in detail. This computer measurement and control software is established on Windows XP operating system, using NET development platform, combined with C# language and Microsoft SQL Serve2005 database, the introduction of ActiveX and Flash animation virtual instrument interface.4. In this test stage, a series of experiments have been carried out on the B1K123-09008 type plant-fin heat exchanger. The results show that: repetitive error of measurement and control system is not greater than 1.5%FS, data accurate and reliability. It meets the research and production process of the plate-fin heat exchanger air resistance characteristics of test requirements. By a large number of experiments on B1K123-09008 type heat exchangers, we get various channel gas flow resistance characteristic curve.