Numerical Analysis and Experimental Assessment of the Cylinder Temperature in a Reciprocating Compressor

Accurate evaluation of the thermal deformation is important to the analysis of reciprocating compressors since the induced deformations are responsible of the thermal stresses on the cylinder. The cylinder body experiences a non-uniform temperature distribution, with the presence of hot and cold spots, creating a bending strain on the structure. A cylinder cooling system is designed to control the uniformity of the temperature field and to reduce the fresh gas heating due to a hot cylinder body, improving the volumetric efficiency. Due to the difficulties associated with obtaining detailed data on the heat transfer processes by experimental means, a more and more important role is played by numerical analysis in reciprocating compressor design. This paper shows the capability of a conjugate heat transfer (CHT) simulation for a double-acting reciprocating compressor cylinder in accurately predicting both the thermal state of the compressor cylinder and the temperature field of the cooling water. The results of the three-dimensional simulations of the water-circuit flow field and the thermal conduction inside the solid metal were compared to temperature measurements collected on a dedicated test bench for both the coolant and the metal structure. Satisfactory agreement was obtained between the experimental data and the numerical computations. In addition, three different modifications for the CHT model were introduced in order to obtain a better match with the experimental results. The suitability of using the CHT simulation as an efficient tool for replicating the actual condition of the reciprocating compressor was analyzed and discussed.

Researcher on Manufacturing Surface of Air Compressor Cylinder by Vibration and Mechanism of Lubrication

The method of the impacting to manufacture micro-pits is put forward in order to reduce friction between Piston ring and Cylinder liner, and improve the effective of air compressor. Method and principium of the impacting to manufacture micro-pits is recounted. The cylinder liner is set on principal axis of the rotating lathe. The tool can feed toward axis or radial direction. The micro-pits deepness is controlled by axis feeding, and distance between two micro-pits is controlled by radial feeding. The motor drives eccentricity wheel, so that the tool engender the low frequency vibration. The micro-pits are manufactured by the tools on low-frequency vibration. The effective of micro-pits processing is improved because the matrix tools were designed and manufactured. The depth of micro-pits can be controlled, so that it is even. The dynamic lubrication is built up between the cylinder and the piston, because the distributing regulation and the structural parameter can be controlled, and the micro-pits distribute evenly and independently. A theoretic model was presented to study the lubrication performance, The theory of dynamic lubrication of the honeycomb micro-pits was researched. The air compressor cylinder liners were manufactured. The tests of air compressors which cylinder liners have no micro-pits and air compressors which cylinder liners have micro-pits were done. The test result proves that friction between Piston ring and Cylinder liner is reduced, and the effective of air compressor is improved because of micro-pits.