Papers by Author: Hong Peng Zhang

Abstract: Hydraulic system is widely used in the ship, when the diameter of tiny particles in hydraulic oil exceeds 20μm it indicates that the abnormal wear occurred and the malfunction may cause. This paper uses the light blockage method, the microfluidic detection chip for hydraulic oil detection has been designed and fabricated, a simple and effective optical detection system is developed with the signal amplification and data collection to achieve the detection of tiny particles, and finally through the JAVA programming to count the number of particles in which the diameter is more than 20μm. The results of rapid detections on iron particles with diameter between 25μm and 38μm show the good performance of the detection system and prove that the method is feasible.

Abstract: Inductance detection methods of metal particle in hydraulic oil are generally based on the inductance change detection. With this method, when particles pass through the microchannel, ferromagnetic and non-ferromagnetic metal particle can be distinguished by monitoring inductance. In this study, it was found that not only inductance pulse but also resistance pulse was produced when detecting particle by inductance detection method. The theory of inductance or resistance change caused by particle is presented from the perspective of electromagnetism in this paper. To verify this phenomenon, the oil sample mixed with different metal particles was forced through the detection coil of microfluidic by constant flow rate. Then several sizes of iron and copper particles were measured. Experimental results showed that the resistance pulses caused by iron particles and copper particles were positive. And for copper particle, SNR (Signal Noise Ratio) of copper particles detected in improved effectively by detecting the resistance pulse.

Abstract: A detection chip is designed and manufactured to study the relationship between iron wear particle content in hydraulic oil and the detected variation of average inductance, which detects content of iron wear particle by means of micro channel - inductive. Through experiments, we obtained inductive values in the cases. The case is that the sizes of iron wear particle are the same, while the content of iron wear particle are different. Thus the curve between content of iron wear particle content and variation of average inductance was drawn. Experimental results show that the inductance value increases with the increase of the iron wear particle content in hydraulic oil. Experiments prove that the way is feasible for the detection of iron wear particle content in hydraulic oil. This study has an important significance for the realization of iron wear particle content detection in hydraulic oil.

Abstract: Metal wear debris is an important component of contamination in lubrication oil, and is also an essential information carrier in hydraulic oil. Based on inductive Coulter counting principle, a microfluidic device to detect metal wear debris in oil is presented in this paper. The proposed device can make the distance between the particles in oil and the embedded induction coil very small, and hence greatly improve the sensitivity of the detection. The results indicate that eddy current within particles increase ability to detect copper particles, and decrease the sensitivity to iron particle.

Abstract: With a piston ring reciprocating liner test rig, the tribological behavior at top dead center of diesel engine was evaluated between hydrorefined mineral oil (HMO) and two kinds of cylinder liner/piston ring, chromium-plated+honing/physical vapor deposition (CP/PVD) and boron-phosphrous alloy cast iron+honing/physical vapor deposition (CI/PVD). Friction coefficient vs. temperature at different loads was used to discriminate the principal function of tribofilm. The analysis shows that the interface between CP/PVD and HMO was subject to thin film lubrication with stearic acid at 70-150°C. When the temperature exceeds 150°C, zinc dialkyl dithiophosphate (ZDDP) began to change the friction status of interface. However, the steady boundary lubrication of CI/PVD exists from 50—250°C at different loads and can not distinguish the scope of additives effects. The reason can be attributed to the chemical reactivity of chromium and iron with the HMO. The soluble Fe2+ or Fe3+ of CI/PVD maybe played an important role in the tribofilm activation level. The understanding provides friction pairs selection at definite lubrication oil and a design guideline for boundary films.

Abstract: Wear debris in hydraulic oil causes most of the faults of hydraulic system and is also an important information carrier, so it is essential to check the condition of wear debris in hydraulic oil. On the basis of inductive principle and microfluidic chip technology, the design of a microfluidic chip of oil detection is presented in this paper. the relation between coil geometry parameters and inductive change of planar inductor are analyzed through the related experimental statistics, the result being that when the ferrous metallic particle flows through planar inductor, the measured inductance variation increases with the number of turns and decreases with the coil line width.