Frontal Suction Methods

Abstract

The basic problem in removing gases or gaseous pollution by suction is the weak suction velocity in free space. This velocity decreases rapidly with the distance to the suction mound or filter area. By creating a frontal vortex, a frontal flow field is induced that blocks and reverses thermal flows. This method increases the efficiency of suction devices that are used, for instance, in kitchen or laboratory environments to remove gases or gaseous pollution by suction. Such aerodynamic flow problems exist also in the space domain. Within ESA projects, the technology provider examines the flight characteristics of Europe’s launchers in wind tunnels. This knowhow has led to the development of Frontal Suction Methods.

Description

The basic problem in removing gases or gaseous pollution by suction is the weak suction velocity in free space. This velocity decreases proportional 1/r², where r is the distance from the suction mound or filter area. Pollutants that are lighter or heavier than the surrounding atmosphere gather under or on top of surfaces (so-called density currents). For example water vapour ascends as a thermal jet. When this jet hits a horizontal surface it spreads under this plane as a density current. The typical example is the flow under a cooker hood (Fig.1).

Fig.1: Illustration of cooker hood working with frontal flow suction method (left) and conventional suction (right).

Conventional technologies use high suction rates to increase the suction flow towards the suction opening or filter areas. However, for many purposes, such as the removal of polluted flows, pure suction is too weak to gather and exhaust accelerated flows dynamically. To increase the range of the suction flow field, additional jets, so-called air-curtains, could be applied. Unfortunately, the air curtain method is not appropriate for fast flows, vapours and strongly heated gas. Such flows are common in most production processes and also in kitchens.

Fig.2: Flow Field generated with Frontal Suction Method. Photo made with a so-called “Schlieren”-optical systemFrontal Suction Methods create flows that block and reverse escaping flows near surfaces. For this purpose, a vortex flow or a circular shear flow is created near to a wall (Fig.1, left). This creates a “dynamical frontal” flow that reaches also into the free space (Fig.2). Polluted gas flows - especially of high velocity - are stopped and transported towards the suction openings.

Frontal flows are generated with specially patented nozzles, so-called Frontal Vortex Generators (FVG), which, depending on their design, produce a frontal flow of either Jet-vortex type or Coanda-vortex type.

Innovations and advantages of the offer

  • better suction efficiency
  • less suction volume flow
  • reduced energy costs
  • allows for smaller suction pipe diameters
  • allows for noise reduction
  • offers possibilities to develop new suction devices and gadgets

Application

Application Fields are:

  • kitchen techniques (use case for current developments)
  • laboratory techniques, fume hood
  • production techniques - soldering or welding working places
  • air curtain doors
  • colour spray techniques

Description of Space Heritage

The technology provider is specialized in solving aerodynamic flow problems for space projects such as ESA’s ELITE initiative, which examines the flight characteristics of Europe’s launchers. By observing how model spacecraft behave in wind tunnels, the company can calculate the effects of very fast airflow on the motion, temperature and physical properties of space vehicles. These experiments help designers to decide on the best materials for building spacecraft, and also to determine the angle and speed at which a vehicle can re-enter the Earth’s atmosphere and land safely.

Category
Other Technologies
Reference No.
TDO0218
Could this technology benefit your business? Please contact Dr. Frank Zimmermann cesah
Discussion
comments powered by Disqus