Research and solution of vibration problem of an air-cooled heat exchanger of reciprocating compressor

Excessive vibration of complex structures in a multi-excitation environment is an arduous problem. Especially in a reciprocating compressor, how to quickly and accurately position the vibration sources, analyze the excitation features and take effective solutions is of great significance to the safe and stable operation of the compressor. In this paper, the problem of excessive vibration of an air-cooled heat exchanger used in a variable speed CH4 compressor was studied. The air-cooled heat exchanger is composed of tubes, tube boxes and support frame. Its vibration is evoked by complex periodic gas pulsation in the tubes. The vibration model of the heat exchanger was simplifies as a multi-freedom model with periodic excitations using the lumped parameter method. The model has advantages of clear physical concept, easy solution and high accuracy of result. In the model, the air-cooled heat exchanger was simplified as three mass blocks connected by six springs. And then, modal test of the heat exchanger was carried out on site. The vibration modes and natural frequencies of the exchanger were obtained according to the test results. After that, above mentioned multi-freedom model was further simplified as a single freedom vibration model, so that it was convenient to propose the vibration control measures. The practical application results proved that these measures were effective. This research provided a practical and fast analytical method for solutions of compressor vibration problems.