Optimum Number of Stages of the New Multi-Stage

Optimum Number of Stages of the New Multi-Stage Symmetrical Wobble Plate Compressor

Ardiyansyah 1*, Md. Nor Musa2 , Wan Ali Wan Mat2, Ainullotfi Abdul Latif4

Faculty of Mechanical Engineering
Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor, Malaysia


Abstract

A new multistage symmetrical wobble plate compressor had been developed. Working pressure is from 3 bar to 206 bar and to compress natural gas for vehicle (NGV). This paper describes on how to get the optimum number of stages of this new Multi-stage symmetrical wobble plate compressor. There are several parameters involved such as load of compressor, torque, work, pressure ratio, and finally the overall size of the compressor. In this design, number of stages start from 3 (three) to 7 (seven). The optimum number of stages optimum for capacity 10 m3/hr at for pressure ratio of 2.27 the optimum number of stages is five certain pressure ratio could be obtained.


Keywords:
Symmetrical Wobble Plate Compressor, Wobble Plate, Compressor, High Pressure, NGV


Introduction

For allowable number of stages chosen and fixed clearance at certain pressure ratio, discharge temperature and efficiency could be calculated. If the calculated discharge temperature in one stage is too high, therefore more stages are required. During preliminary sizing, the isentropic discharge temperature could be used, but if a certain number of stages create a marginal situation, the discharge temperature should be estimated more accurately. As a first estimate, it can be assumed that equal pressure ratios are used for all stages. In practice it is often better to take a higher-pressure ratio in the low-pressure ratio stages and unload the more critical higher-pressure stages a little.
If stages number is to high, the pressures losses in the valve and piping will offset the gains from inter cooling and the efficiency would be reduced. The cost of the compressor to do a given task usually increases as the number of stages is increased because of the additional compressor cylinder, coolers and piping needed.
In this case, a symmetrical wobble plate compressor could be used to compress a natural gas. An operating conditions are suction pressure 50 psi (3 bar), discharge pressure 3000 psi (206 bar), and capacity 10Nm3/hr. There are several parameters involve in getting the optimum number of stages i. e., load of compressor, torque, work, pressure ratio, and finally is overall size of the compressor.
In this design process the number of design stages will be start from 3 (three) until 7 (seven) and the optimum number of stages could be obtained at certain pressure ratio.


Conclusion
Based on the analysis, we conclude that the optimum number of stages for capacity 10 m3/hr is 5.



Reference

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