Vortex Flow Meter

DESCRIPTION OF PRODUCTS

HLUG series smart vortex flowmeter is mainly used for measuring flow of industrial pipeline fluid, such as gas,liquid and steam, etc. It has little pressure loss, broad span range and high accuracy. It is not under influence of density, pressure, temperature and viscocity when measuring volumetric flow. It has no movable mechanical parts with high reliability and little maintenance.PERFORMANCES & FEATURES

OPERATION PRINCIPLES

Setting vortex generation body (bluff body) in fluid, regular vortexs will alternately generate from two
sides of vortex generation body. This kind of vortex is called Karman vortex. See picture 1. Vortex is at
downstream of vortex generation body, unsymmetrical array. Set occurrence to be f , avarage flow
speed of measured medium U, face width d and diameter D. According to Karman principle, exsiting
following relation :
f = StU1/d = StU/md
U1 - avarage flow speed at two sides of vortex generation body, m/s
St - Strouhal number
m – ratio of segment area and pipeline cross sectional area 

K has relation with vortex generation body, pipeline dimension and Strouhal nember. Strouhal nember is
a parameter without dimension. It has something to do with shape of vortex generation body and
reynolds number. Seeing from the picture, in the range of Re = 2 * 104 ~ 7 * 106, St can be seen to be a
constant. When measuring gas flow, flow calculation formula of HLUG is In the formula, Qvn, Q --- volumetric flow under standard conditions and working conditions, m3/h ,Pn, P --- absolute pressure under standard conditions and working conditions, Pa. 

Tn, T --- thermodynamics temperature under standard conditions and working conditions, K
Zn, Z --- gas compression coefficient under standard conditions and working conditions
Seeing from the above formula, pulse frequency signal output by HLUG is not influenced by fluid
physical properties and component changes, that is, instrument coefficient only has relation with vortex
generation body and dimension of pipeline in a certain range of reynold number. But the flowmeter must
measure mass flow in material balance and energy measurment, here output signal of flowmeter should
monitor volumetric flow and fluid density, therefore, fluid physical properties and component have direct
influence on flow measurement.

STRUCTURE & DIMENSION
This series vortex flowmeter has two types of connection forms and dimension .

MODEL SELECTION & CALCULATION

1. Caliber of flowmeter should be chosen according to max working flow Qv; to get much wider working
flow range, max working flow should be not less than 1/2 of rated max flow Qmax. Corresponding
reynold number range of linear flow range is 2 * 104 ~ 7 8*106.
For liquid, please look up in sheet 2 according to picture 9; for gas please work out flow range under
working conditions according to picture 10, looking up in sheet 2.

2. Change flow under standard conditions into flow under working conditions
(1) Change density ρn under standard conditions into ρ under working conditions
(2) Calculate flow Q under working conditions
a. Find out Qv by Qn under standard conditions
b. Find out Qv by mass flow Qm
3. Conversion between Dynamic viscosity μ and moving viscosity v
ρ –density under working conditions (kg/m3)
ρn- density under standard conditions (kg/m3)
P – pressure under working conditions (MPa)
T – temperature under working conditions (°C)
Qv – flow under working conditions (m3/h)
Qn – flow under standard conditions (m3/h)
Qm – mass flow (kg/h)