Sakthi Subramanian wrote:

i have opened a capture device, and the captured data i have written to a file. That file is of RAW format. I have opened the raw file in audacity, with 8 channel it shows only 2 channels having the captured data.

Raw-format files do not have any information about the format, so Audacity has to guess. Just write a .wav file with the proper headers.

Regards, Clemens