The Banki Water Turbine – Download as PDF File .pdf), Text File .txt) or read online. the Michell turbine is 80 percent or great-. The efficiency of er. This, along with its adaptability to a variety of water sites and power needs, and its simplicity and. The results of the experiments were produced in this document titled the Banki Water Turbine by C.A Mockmore & Fred Merryfield, Bulletin Series No, Feb.

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This article is intended to help you build your own cross-flow turbine, also known as a Mitchell-Banki turbine. Mitchell is the original inventor of the turbine around Banki took up this design and explained its theory of operation in The results of the experiments were produced in this document titled the Banki Water Turbine by C.

The low efficiency that Mockmore and Merryfield achieved may turbinr due in part to the nozzle design; the Banki nozzle was close coupled to the turbine such that the nozzle outlet pressure may have been higher than atmospheric, as compared to the Mockmore and Merryfield design that came in at atmospheric pressure.

Their nozzle is also close-coupled and the water enters many turbine blades perhaps being responsible for the higher efficiency.

Lately, I have come across a paper by W. Fay titled “Some fluid characteristics of a cross-flow type hydraulic turbine”. You can download this paper here: The web site where I discovered this paper is: This paper shows that the cross-flow turbine watre be unstable at certain flow rates and that cross-flow through the turbine bbanki not always occur.

The other reason to consider it is easier to build than to the Pelton.


A cross-flow turbine is a type of turbine that is suitable for low head high flow applications. This is probably a more frequent application than the high head low flow application for which a Pelton turbine is designed. Also a homeowner can more easily build a cross-flow turbine because the turbine blades are a simple shape compared to the complex buckets of the Pelton turbine, however you can buy a Pelton wheel only.

How much flow is available? This is the first item to consider. It is beyond the purview of this article to explain how to determine this but I think that most people will be able to determine whether wate is suitable rurbine tap their water source with a 2″, 6,” or 10″ diameter pipe.

This web site will give you some ideas as to how to go about it:. This article will be based on the information provided in the C.

Cross-flow turbine

The remarkable thing about this design is that the water jet enters the turbine tangentially, goes through the blades of a simple circular section, crosses the inside of the turbine and impacts the blades on the other side at an angle that allows more power to be extracted from the water jet.

Here is a nice image of the turbine which I borrowed from Joe Cole’s website for which I am grateful and will ask for his permission to use when I manage to reach him. The following image shows the passage of the water jet through the turbine. The centerline of wzter water jet is shown as the dashed red line. The water strikes the turbine blade rotating the whole turbine wheel.

Design and calculations for the cross-flow turbine

This rotation moves the water jet forward until it has passed over the blade and fallen through the center of the turbine. Before we get into the details as to how to size your turbine and how to determine the power available from the water jet, there are certain geometrical constants that make a cross-flow turbine what it is and thereby ensure that you get close to it’s highest possible efficiency.


These features are shown in Figure 4. The water jet angle to the blades should be 16 degrees bnki respect to the tangent at the point of contact more about the width of the water jet later. The leading edge of the blade should be at 30 degrees to the tangent at the point of contact.

Banki Turbines – Hydro – IREM power quality, turbine idroelettriche, illuminazione professionale

The trailing edge of the blade is radial, that is all the trailing edges point directly to the center. The blades are made from circular sections of radius rb and the spacing t will be calculated depending on the overall diameter d 1 of the awter. I am merely extracting from that document the relevant formulas that are used for sizing the turbine. We will start our turbine tutbine using an outside diameter of 12″. I will be using the Imperial system of measurements.

You can visit their web site here: Dimensions and power extraction capacity of the cross-flow turbine A ganki turbine is a type of turbine that is suitable for low head high flow applications.

This web site will give you some ideas as to how to go about it: Water flow through the cross-flow turbine.

Critical geometry of the cross-flow turbine.