Effect of Graphite and Carbon Nanofiber Additives on the Performance Efficiency of a Gear Pump Driven Hydraulic Circuit Using Ethanol

Abstract

We show that fine graphite flake and carbon nanofiber dispersed ethanol solutions can potentially replace conventional hydraulic fluids in gear pump-driven hydraulic circuits operating below 1 MPa gauge pressure. Low-viscosity hydraulic fluids are generally detrimental to pump life. However, both graphite and carbon nanofiber dispersions in ethanol within a concentration range of 195-1500 ppm can sustain hydraulic circuits with increases in pump efficiency and without modifying the viscosity of ethanol. Pump inlet pressure, volumetric flow rate, and electric power consumption data were recorded over a range of pump discharge pressures. Pump power consumption at a given differential pump pressure was found to remain approximately constant for all suspensions. However, increases in both volumetric flow rate and overall pump efficiency were observed when pure ethanol was replaced by the nanostructured carbon/ethanol solutions. The presence of the additives can partially or collectively improve a number of lubrication mechanisms which exist in a gear pump such as boundary, hydrodynamic, hydrostatic, elastohydrodynamic, and mixed-film lubrication. Additionally, we observed that the additives deposited permanently on gear and enclosure surfaces creating low shear strength films which can help reduce friction. Qualitative examination of environmental scanning electron microscope images of colloidal graphite and carbon nanofiber additive morphology before and after extended run periods indicated that graphite retained significant resilience, whereas carbon nanofibers appear to have undergone some scission.

Effect of Nano Hexagonal Boron Nitride Lubricant Additives on the Friction and Wear Properties of AISI 4140 Steel

“…The major solid lubricants include MoS 2 , graphite, boric acid, boron nitride, PTFE, diamond, soft metals, and lubricious oxides (Ladavière et al 2003, Donnet and Erdemir 2004, Erdemir 2009, Hu et al 2009). The tribological properties of oil additives, such as MoS 2 (Gansheimer and Holinski 1973;Ilie and Tita 2006;Prasad et al 2011), graphite (Huang et al 2006;Martorana et al 2010;Prasad et al 2011), graphene (Eswaraiah et al 2011;Wei et al 2011), boric acid (Erdemir 2009;Lovell et al 2010;Vadiraj et al 2012), nano-diamond (Wu et al 2007;Lee 2008, 2010;Chu et al 2010), PTFE (Rico et al 2007), and others (Xue et al 1997;Chen et al 1998;Sunqing et al 1999;Liu and Chen 2000;Rapoport et al 2003;Hernandez Battez et al 2006;Wu et al 2007;Gu et al 2008;Hernández Battez et al 2008;Yang et al 2009;Hernández Battez et al 2010;Peng et al 2010), have been reported in the literature.…”

Flow and Heat Transfer Property of Oldroyd-B-Fluid-Based Nanofluids Containing Cylindrical Particles in a Pipe

“…Most of these studies use Newtonian fluids as the base fluids, and many valuable conclusions are obtained. For example, nanoscale additives could to reduce friction in [4]. Using water-CuO causes 13.8, 1.5 and 1.3% higher thermal efficiency in comparison with employing pure water, water-TiO 2 and water-Al 2 O 3 nanofluids, respectively, in a U-shaped solar tube collector [5].…”

Nano graphite as additive in soybean oil

“…Martorana et al [9] reported that ethanol containing graphite for gear pump proved to be significantly resilience without undergoing scission and degradation during running, but without significantly increasing the viscosity of the lubricant.…”