![]() ![]() Importantly, the graphs can be saved for use in the users own reports. Registration takes just seconds and only requires name, company and email address. Equations are provided for calculating viscosity index for petroleum products having kinematic viscosities above 70 mm2/s (cSt) at 100☌. More detailed results, including graphs (some in 3D), can be accessed by logging in (existing users) or registering (new users). This free-of-charge Webtec app is the company’s ‘light’ version. Calculator for viscosity index (VI) according to ASTM D2270 and ISO 2909. But as motor oil technology advanced, additives such as viscosity index improvers allowed for the use of the same grade of oil year-round. To see the effects on viscosity of fluctuations in temperature or pressure, the user simply alters the values in these fields accordingly, making hydraulic measurement and control easy to achieve. Standard practice for calculating viscosity index from kinematic viscosity at 40 and 100☌. Using Webtec’s app, engineers simply select the oil being used, along with the system temperature (☌) and pressure (bar), hit the ‘submit’ button and up pops the viscosity (cSt). These oils are most-often badged in terms of their ISO number or grade, where common grades for hydraulic circuits include ISO 32, 46 and 68. Hydraulic fluid suppliers provide oils with different viscosities. Where VBN is the viscosity blending number of the blend and e is the transcendental number 2.71828, also known as Euler's number.Webtec has launched a new on-line hydraulic oil viscosity calculator app which calculates the viscosity of hydraulic oil at different pressures. Once the viscosity blending number of a blend has been calculated using equation (2), the third and final step is to determine the viscosity of the blend by using the invert of equation (1): Where w is the weight fraction (i.e., weight % ÷ 100) of each component of the blend. An on-line calculator, well accepted by experts in the field, was used to generate viscosity index. The next step is to calculate the VBN of the blend, using this equation: viscosity index calculations, once converted to cSt. It is important that the viscosity of each component of the blend be obtained at the same temperature. The VI of a highly refined mineral oil (hydrotreated) can be up to 120. A traditional mineral oil has a viscosity index between 95 to 100. Any warranties as to the quality of marine. The VI of conventional mineral oils roughly ranges between 0 and 100, for modified mineral oils between 125 and 150, for synthetic esters between 140 and 160 and for silicone oils up to 200. These measurements are then compared to the results of two reference oils. This document is supplied for information only and is not part of any contract for the supply of marine fuels. A high VI-value indicates smaller viscosity changes with temperature. Table 1 given in this practice applies to petroleum products with kinematic viscosities between 2 mm 2 /s and 70 mm 2 /s at 100 ☌. Where v is the viscosity in square millimeters per second (mm²/s) or centistokes (cSt) and ln is the natural logarithm (log e). The viscosity index of a lubricant is determined by measuring the kinematic viscosity at 40☌ and 100☌. Lower viscosity motor oils also result in better fuel economy. These lower viscosity motor oils are needed to move through the thin engine pathways to protect and clean metal surfaces. The term 0 is the experimental viscosity at shear stress approaching zero. Where the term is the experimental value at high shear stress. Reiner and Phillippoff suggested the following formula: dUx dy ( 1 + 0 1 + ( xy s)2)xy. This indicates that the base oil has a high viscosity index, making it suitable for applications where temperature. The calculator will display the viscosity index, which, in this case, is approximately 162. The first step is to calculate the Viscosity Blending Index (VBI) of each component of the liquid blend using the following equation: This has led over time to motor oil viscosity decreasing currently 5W-30 and 5W-20 are the most popular grade and 0W-20 is the fastest growing grade. The higher viscosity is more dominate at low shear stress. Input the kinematic viscosity at 40C (L): 75 cSt Enter the kinematic viscosity at 100C (H): 10 cSt Click Calculate. Liquid viscosity blending calculations to determine the viscosity of a blend of two or more liquids having different viscosities are best performed by using what is known as the Refutas equation in a three-step procedure. ![]()
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